%% Books @book{fds42606, Title = {Nonperturbative Quantum Chromodynamics. Proceedings, 8th Workshop, Paris, France, June 7-11, 2004}, Journal = {Int. J. Mod. Phys. A}, Volume = {20}, Pages = {4363-4697}, Editor = {B. Müller and C. I. Tan}, Year = {2005}, url = {http://worldscinet.com/ijmpa/20/2019/S0217751X052019.html}, Key = {fds42606} } @book{fds14750, Author = {J. Kapusta and B. Müller and J. Rafelski}, Title = {Quark-Gluon Plasma - Theoretical Foundations (An annotated reprint collection).}, Publisher = {Elsevier}, Year = {2003}, Key = {fds14750} } @book{fds38417, Title = {Quantum Chromodynamics. Proceedings, 7th Workshop, Villefranche-s-Mer, France, January 6-10, 2003}, Publisher = {World Scientific}, Editor = {H. M. Fried and B. Müller and Y. Gabellini}, Year = {2003}, Key = {fds38417} } @book{fds38416, Title = {Non-Perturbative QCD, Proceedings, 6th Workshop, Paris, France, June 5-9, 2001}, Publisher = {World Scientific}, Editor = {H. M. Fried and Y. Gabellini and B. Müller}, Year = {2002}, Key = {fds38416} } @article{Fried:2000jc, Title = {Quantum Chromodynamics. Proceedings 5th Workshop, Villefranche-s-Mer, France, January 3-7, 2000}, Publisher = {World Scientific}, Editor = {H. M. Fried and B. Müller}, Year = {2001}, Key = {Fried:2000jc} } @article{Fried:1999kn, Title = {Quantum chromodynamics. Proceedings, 4th Workshop, Paris, France, June 1-6, 1998}, Publisher = {World Scientific}, Editor = {H. M. Fried and B. Müller}, Year = {1999}, Key = {Fried:1999kn} } @article{Muller:1999br, Title = {RHIC Physics and Beyond -- Kay Kay Gee Day}, Publisher = {American Institute of Physics (CP 482)}, Editor = {B. Müller and R. D. Pisarski}, Year = {1999}, Key = {Muller:1999br} } @article{Fried:1997sp, Title = {Quantum chromodynamics: Collisions, confinement and chaos. Proceedings, 3rd Workshop on Fundamental Physics, Paris, France, June 3-8, 1996}, Publisher = {World Scientific}, Editor = {B. Fried and B. Müller}, Year = {1997}, Key = {Fried:1997sp} } @article{Muller:1995he, Author = {B. Müller and J. Reinhardt and M. T. Strickland}, Title = {Neural networks: An Introduction}, Publisher = {Springer-Verlag}, Year = {1995}, Key = {Muller:1995he} } @article{Fried:1995iv, Title = {Quantum infrared physics. Proceedings, Workshop, Paris, France, June 6-10, 1994}, Publisher = {World Scientific}, Editor = {H. M. Fried and B. Müller}, Year = {1995}, Key = {Fried:1995iv} } @article{Biro:1995jc, Author = {T. S. Biro and S. G. Matinyan and B. Müller}, Title = {Chaos and Gauge Field Theory}, Publisher = {World Scientific}, Year = {1995}, Key = {Biro:1995jc} } @article{Greiner:1993sl, Author = {W. Greiner and B. Müller}, Title = {Quantum mechanics II: Symmetries}, Publisher = {Springer-Verlag}, Year = {1994}, Key = {Greiner:1993sl} } @article{Greiner:1993qp, Author = {W. Greiner and B. Müller}, Title = {Gauge theory of weak interactions}, Publisher = {Springer-Verlag}, Year = {1993}, Key = {Greiner:1993qp} } @article{Fried:1993jr, Title = {QCD vacuum structure. Proceedings, Workshop, Paris, France, June 1-5, 1992}, Publisher = {World Scientific}, Editor = {H. M. Fried and B. Müller}, Year = {1993}, Key = {Fried:1993jr} } @article{Fried:1991up, Title = {Vacuum structure in intense fields. Proceedings, NATO Advanced Study Institute, Cargese, France, July 31 - August 10, 1990}, Publisher = {Plenum Press}, Editor = {H. M. Fried and B. Müller}, Year = {1991}, Key = {Fried:1991up} } @article{Muller:1985ed, Author = {B. Müller}, Title = {The physics of the quark-gluon plasma}, Publisher = {Springer-Verlag (LNP 225)}, Year = {1985}, Key = {Muller:1985ed} } @book{fds38418, Author = {W. Greiner and B. Müller and J. Rafelski}, Title = {Quantum Electrodynamics of Strong Fields}, Publisher = {Springer-Verlag}, Year = {1985}, Key = {fds38418} } %% Papers Published @article{fds333318, Author = {Müller, B and Schäfer, A}, Title = {Hot spaghetti: Viscous gravitational collapse}, Journal = {The European Physical Journal A - Hadrons and Nuclei}, Volume = {54}, Number = {2}, Year = {2018}, Month = {February}, url = {http://dx.doi.org/10.1140/epja/i2018-12411-0}, Abstract = {© 2018, SIF, Springer-Verlag GmbH Germany, part of Springer Nature. We explore the fate of matter falling into a macroscopic Schwarzschild black hole for the simplified case of a radially collapsing thin spherical shell for which the back reaction of the geometry can be neglected. We treat the internal dynamics of the in-falling matter in the framework of viscous relativistic hydrodynamics and calculate how the internal temperature of the collapsing matter evolves as it falls toward the Schwarzschild singularity. We find that viscous hydrodynamics fails when either the dissipative radial pressure exceeds the thermal pressure and the total radial pressure becomes negative, or the time scale of variation of the tidal forces acting on the collapsing matter becomes shorter than the characteristic hydrodynamic response time.}, Doi = {10.1140/epja/i2018-12411-0}, Key = {fds333318} } @article{fds333319, Author = {Biró, T and Greiner, C and Müller, B and Rafelski, J and Stöcker, H}, Title = {Topical Issue on Frontiers in Nuclear, Heavy Ion and Strong Field Physics}, Journal = {The European Physical Journal A - Hadrons and Nuclei}, Volume = {54}, Number = {2}, Year = {2018}, Month = {February}, url = {http://dx.doi.org/10.1140/epja/i2018-12477-6}, Doi = {10.1140/epja/i2018-12477-6}, Key = {fds333319} } @article{fds331489, Author = {Koch, P and Müller, B and Rafelski, J}, Title = {From strangeness enhancement to quark–gluon plasma discovery}, Journal = {International Journal of Modern Physics A}, Volume = {32}, Number = {31}, Pages = {1730024-1730024}, Year = {2017}, Month = {November}, url = {http://dx.doi.org/10.1142/S0217751X17300241}, Doi = {10.1142/S0217751X17300241}, Key = {fds331489} } @article{fds331199, Author = {Yao, X and Mehen, T and Müller, B}, Title = {Dynamical screening of resonant scattering and thermal nuclear scattering rate in a plasma}, Journal = {Physical Review D}, Volume = {95}, Number = {11}, Year = {2017}, Month = {June}, url = {http://dx.doi.org/10.1103/PhysRevD.95.116002}, Doi = {10.1103/PhysRevD.95.116002}, Key = {fds331199} } @article{fds332872, Author = {Müller, B}, Title = {The future of RHIC}, Journal = {PoS - Proceedings of Science}, Volume = {2017-January}, Year = {2017}, Month = {January}, Abstract = {© Copyright owned by the author(s). This article describes recent results and future plans for the Relativistic Heavy Ion Collider.}, Key = {fds332872} } @article{fds322935, Author = {Yang, D-L and Müller, B}, Title = {Shear viscosities of photons in strongly coupled plasmas}, Journal = {Physics Letters B}, Volume = {760}, Pages = {565-570}, Year = {2016}, Month = {September}, url = {http://dx.doi.org/10.1016/j.physletb.2016.07.034}, Doi = {10.1016/j.physletb.2016.07.034}, Key = {fds322935} } @article{fds331490, Author = {Accardi, A and Albacete, JL and Anselmino, M and Armesto, N and Aschenauer, EC and Bacchetta, A and Boer, D and Brooks, WK and Burton, T and Chang, N-B and Deng, W-T and Deshpande, A and Diehl, M and Dumitru, A and Dupré, R and Ent, R and Fazio, S and Gao, H and Guzey, V and Hakobyan, H and Hao, Y and Hasch, D and Holt, R and Horn, T and Huang, M and Hutton, A and Hyde, C and Jalilian-Marian, J and Klein, S and Kopeliovich, B and Kovchegov, Y and Kumar, K and Kumerički, K and Lamont, MAC and Lappi, T and Lee, J-H and Lee, Y and Levin, EM and Lin, F-L and Litvinenko, V and Ludlam, TW and Marquet, C and Meziani, Z-E et al.}, Title = {Electron-Ion Collider: The next QCD frontier}, Journal = {The European Physical Journal A - Hadrons and Nuclei}, Volume = {52}, Number = {9}, Year = {2016}, Month = {September}, url = {http://dx.doi.org/10.1140/epja/i2016-16268-9}, Doi = {10.1140/epja/i2016-16268-9}, Key = {fds331490} } @article{fds331200, Author = {Yao, X and Mehen, T and Müller, B}, Title = {An effective field theory approach to the stabilization of 8 Be in a QED plasma}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {43}, Number = {7}, Pages = {07LT02-07LT02}, Year = {2016}, Month = {July}, url = {http://dx.doi.org/10.1088/0954-3899/43/7/07LT02}, Doi = {10.1088/0954-3899/43/7/07LT02}, Key = {fds331200} } @article{fds247169, Author = {Müller, B and Yang, D-L}, Title = {Viscous leptons in the quark gluon plasma}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {91}, Number = {12}, Year = {2015}, Month = {June}, ISSN = {1550-7998}, url = {http://dx.doi.org/10.1103/PhysRevD.91.125010}, Doi = {10.1103/PhysRevD.91.125010}, Key = {fds247169} } @article{fds247168, Author = {Muller, B}, Title = {PHENIX and the quest for the quark-gluon plasma}, Journal = {Progress of Theoretical and Experimental Physics}, Volume = {2015}, Number = {3}, Pages = {3A103}, Year = {2015}, Month = {January}, url = {http://ptep.oxfordjournals.org/cgi/content/full/ptu137?ijkey=DAefZTjUnytOCaA&keytype=ref}, Abstract = {http://ptep.oxfordjournals.org/cgi/content/abstract/ptu137?ijkey=DAefZTjUnytOCaA&keytype=ref}, Doi = {10.1093/ptep/ptu137}, Key = {fds247168} } @article{fds247170, Author = {Coleman-Smith, C and Müller, B}, Title = {How to catch a ‘fat’ proton}, Journal = {Annals of Physics}, Volume = {352}, Pages = {59-69}, Year = {2015}, Month = {January}, ISSN = {0003-4916}, url = {http://dx.doi.org/10.1016/j.aop.2014.07.040}, Doi = {10.1016/j.aop.2014.07.040}, Key = {fds247170} } @article{fds247171, Author = {Asakawa, M and Bass, SA and Mueller, B}, Title = {Center domains and their phenomenological consequences in ultrarelativistic heavy ion collisions}, Journal = {Nuclear Physics A}, Volume = {931}, Pages = {1120-1124}, Year = {2014}, Month = {November}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2014.08.005}, Abstract = {© 2014 Elsevier B.V. We argue that the domain structure of deconfined QCD matter, which can be inferred from the properties of the Polyakov loop, can simultaneously explain the two most prominent experimental features of the quark-gluon plasma, namely its near ideal fluid properties and its large opacity.}, Doi = {10.1016/j.nuclphysa.2014.08.005}, Key = {fds247171} } @article{fds247173, Author = {Asakawa, M and Bass, SA and Mueller, B}, Title = {Center domains and their phenomenological consequences in ultrarelativistic heavy ion collisions}, Journal = {Nuclear Physics A}, Volume = {931}, Pages = {1120-1124}, Year = {2014}, Month = {November}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2014.08.005}, Doi = {10.1016/j.nuclphysa.2014.08.005}, Key = {fds247173} } @article{fds247172, Author = {Burke, KM and Buzzatti, A and Chang, N and Gale, C and Gyulassy, M and Heinz, U and Jeon, S and Majumder, A and Müller, B and Qin, G-Y and Schenke, B and Shen, C and Wang, X-N and Xu, J and Young, C and Zhang, H}, Title = {Extracting the jet transport coefficient from jet quenching in high-energy heavy-ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {90}, Number = {1}, Pages = {015909}, Year = {2014}, Month = {July}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.90.014909}, Abstract = {http://arxiv.org/abs/1312.5003}, Doi = {10.1103/PhysRevC.90.014909}, Key = {fds247172} } @article{fds247174, Author = {Qin, G-Y and Müller, B}, Title = {Elliptic and triangular flow anisotropy in deuteron-gold collisions at GeV at RHIC and in proton-lead collisions at TeV at the LHC}, Journal = {Physical Review C - Nuclear Physics}, Volume = {89}, Number = {4}, Pages = {044902}, Year = {2014}, Month = {April}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.89.044902}, Abstract = {http://arXiv.org/abs/1306.3439}, Doi = {10.1103/PhysRevC.89.044902}, Key = {fds247174} } @article{fds247176, Author = {Coleman-Smith, CE and Müller, B}, Title = {Mapping the proton’s fluctuating size and shape}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {89}, Number = {2}, Pages = {025019}, Year = {2014}, Month = {January}, ISSN = {1550-7998}, url = {http://dx.doi.org/10.1103/PhysRevD.89.025019}, Abstract = {http://arXiv.org/abs/1307.5911}, Doi = {10.1103/PhysRevD.89.025019}, Key = {fds247176} } @article{fds247177, Author = {Müller, B and Wu, S-Y and Yang, D-L}, Title = {Elliptic flow from thermal photons with magnetic field in holography}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {89}, Number = {2}, Pages = {025019}, Year = {2014}, Month = {January}, ISSN = {1550-7998}, url = {http://dx.doi.org/10.1103/PhysRevD.89.026013}, Abstract = {http://arxiv.org/abs/1308.6568}, Doi = {10.1103/PhysRevD.89.026013}, Key = {fds247177} } @article{fds247178, Author = {Caceres, E and Kundu, A and Müller, B and Vaman, D and Yang, DL}, Title = {Jet quenching and holographic thermalization}, Journal = {AIP Conference Proceedings}, Volume = {1560}, Pages = {672-674}, Year = {2013}, Month = {December}, ISSN = {0094-243X}, url = {http://dx.doi.org/10.1063/1.4826868}, Abstract = {We employ the AdS/CFT correspondence to investigate the thermalization of the strongly-coupled plasma and the jet quenching of a hard probe traversing such a thermalizing medium. © 2013 AIP Publishing LLC.}, Doi = {10.1063/1.4826868}, Key = {fds247178} } @article{fds247182, Author = {Balasubramanian, V and Bernamonti, A and de Boer, J and Craps, B and Franti, L and Galli, F and Keski-Vakkuri, E and Müller, B and Schäfer, A}, Title = {Inhomogeneous thermalization in strongly coupled field theories.}, Journal = {Physical Review Letters}, Volume = {111}, Number = {23}, Pages = {231602}, Year = {2013}, Month = {December}, ISSN = {0031-9007}, url = {http://arXiv.org/pdf/1307.1487}, Abstract = {To describe theoretically the creation and evolution of the quark-gluon plasma, one typically employs three ingredients: a model for the initial state, nonhydrodynamic early time evolution, and hydrodynamics. In this Letter we study the nonhydrodynamic early time evolution using the AdS/CFT correspondence in the presence of inhomogeneities. We find that the AdS description of the early time evolution is well matched by free streaming. Near the end of the early time interval where our analytic computations are reliable, the stress tensor agrees with the second order hydrodynamic stress tensor computed from the local energy density and fluid velocity. Our techniques may also be useful for the study of far-from-equilibrium strongly coupled systems in other areas of physics.}, Doi = {10.1103/physrevlett.111.231602}, Key = {fds247182} } @article{fds247179, Author = {Müller, B}, Title = {Investigation of hot QCD matter: theoretical aspects}, Journal = {Physica Scripta: an international journal for experimental and theoretical physics}, Volume = {T158}, Pages = {014004-014004}, Year = {2013}, Month = {December}, ISSN = {0031-8949}, url = {http://arxiv.org/pdf/1309.7616}, Abstract = {http://arxiv.org/abs/1309.7616}, Doi = {10.1088/0031-8949/2013/T158/014004}, Key = {fds247179} } @article{fds324420, Author = {Balasubramanian, V and Bernamonti, A and de Boer, J and Craps, B and Franti, L and Galli, F and Keski-Vakkuri, E and Mueller, B and Schaefer, A}, Title = {Inhomogeneous holographic thermalization}, Journal = {The Journal of High Energy Physics}, Volume = {10}, Number = {10}, Pages = {082}, Year = {2013}, Month = {October}, url = {http://arxiv.org/pdf/1307.7086}, Abstract = {http://arxiv.org/abs/1307.7086}, Doi = {10.1007/JHEP10(2013)082}, Key = {fds324420} } @article{fds247187, Author = {Coleman-Smith, CE and Mueller, B}, Title = {What can we learn from dijets? A systematic study at RHIC with VNI/BMS.}, Journal = {Nuclear Physics A}, Volume = {910}, Pages = {429-432}, Year = {2013}, Month = {August}, ISSN = {0375-9474}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000322930900083&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Doi = {10.1016/j.nuclphysa.2012.12.014}, Key = {fds247187} } @article{fds247188, Author = {Kapusta, JI and Mueller, B and Stephanov, M}, Title = {Hydrodynamic noise and Bjorken expansion}, Journal = {Nuclear Physics A}, Volume = {904}, Pages = {499C-502C}, Year = {2013}, Month = {May}, ISSN = {0375-9474}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000320486100082&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Doi = {10.1016/j.nuclphysa.2013.02.062}, Key = {fds247188} } @article{fds247197, Author = {Coleman-Smith, CE and Mueller, B}, Title = {A "Helium atom" of space: Dynamical instability of the isochoric pentahedron}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {87}, Number = {4}, Pages = {044047}, Year = {2013}, Month = {February}, ISSN = {1550-7998}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000315280300008&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {http://arxiv.org/abs/1212.1930}, Doi = {10.1103/PhysRevD.87.044047}, Key = {fds247197} } @article{fds220245, Author = {Petersen, H. and Müller, B.}, Title = {On the possibility of event shape selection in relativistic heavy ion collisions}, Journal = {Phys. Rev. C}, Volume = {88}, Pages = {044918}, Year = {2013}, url = {http://arXiv.org/pdf/1305.2735}, Abstract = {http://arXiv.org/abs/1305.2735}, Key = {fds220245} } @article{fds218430, Author = {Müller, B. and Yang, D.L.}, Title = {Light probes in a strongly coupled anisotropic plasma}, Journal = {Phys. Rev. D}, Volume = {87}, Pages = {046004}, Year = {2013}, url = {http://arxiv.org/pdf/1212.1930}, Abstract = {http://arxiv.org/abs/1212.1930}, Key = {fds218430} } @article{fds247167, Author = {Coleman-Smith, C and Müller, B}, Title = {How to catch a 'fat' proton}, Journal = {Annals of Physics}, Year = {2013}, ISSN = {0003-4916}, url = {http://dx.doi.org/10.1016/j.aop.2014.07.040}, Abstract = {© 2014 Elsevier Inc.We argue that high-multiplicity events in proton-proton or proton-nucleus collisions originate from large-size fluctuations of the nucleon shape. We discuss a pair of simple models of such proton shape fluctuations. A "fat" proton with a size of 3fm occurs with observable frequency. In light of this result, collective flow behavior in the ensuing nuclear interaction seems feasible. We discuss the influence of these models on the parton structure of the proton.}, Doi = {10.1016/j.aop.2014.07.040}, Key = {fds247167} } @article{fds247181, Author = {Cao, S and Qin, G-Y and Bass, SA and Mueller, B and IOP}, Title = {Heavy quark energy loss and angular de-correlation in a quark-gluon plasma matter}, Journal = {Journal of Physics}, Volume = {446}, Pages = {012035-012035}, Year = {2013}, url = {http://dx.doi.org/10.1088/1742-6596/446/1/012035}, Doi = {10.1088/1742-6596/446/1/012035}, Key = {fds247181} } @article{fds247184, Author = {Iida, H and Kunihiro, T and Müller, B and Ohnishi, A and Schäfer, A and Takahashi, TT}, Title = {Entropy production in classical Yang-Mills theory from glasma initial conditions}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {88}, Number = {9}, Year = {2013}, ISSN = {1550-7998}, url = {http://dx.doi.org/10.1103/PhysRevD.88.094006}, Abstract = {We study the thermalization process in classical Yang-Mills field theory starting from noisy glasmalike initial conditions by investigating the initial-value sensitivity of trajectories. Kunihiro et al. linked entropy generation to the Kolmogorov-Sinaï entropy, which gives the entropy production rate in classical chaotic systems, calculated numerically for classical Yang-Mills fields starting from purely random initial field configurations. In contrast, we study here glasmalike initial conditions. For small random fluctuations, we obtain qualitatively similar results, while no entropy increase is observed when such fluctuations are absent. We analyze the intermediate-time Lyapunov spectrum for several time windows and calculate the Kolmogorov-Sinaï entropy. We find a large number of positive Lyapunov exponents at the early stages of time evolution. Also, for later times, their number is a sizeable fraction of the total number of degrees of freedom. The spectrum of positive Lyapunov exponents at first changes rapidly but then stabilizes, indicating that the dynamics of the gauge fields approaches a steady state. Thus, we conclude that also for glasmalike initial conditions, a significant amount of entropy is produced by classical gluon field dynamics. © 2013 American Physical Society.}, Doi = {10.1103/PhysRevD.88.094006}, Key = {fds247184} } @article{fds247185, Author = {Petersen, H and Müller, B}, Title = {Possibility of event shape selection in relativistic heavy ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {88}, Number = {4}, Year = {2013}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.88.044918}, Abstract = {We investigate the possibility of selecting heavy ion collision events with certain features in the initial state (event engineering). Anisotropic flow measurements in heavy ion reactions have confirmed the almost ideal fluid dynamical behavior of the hot and dense quark-gluon plasma state. As a consequence, it is intriguing to pursue the idea of selecting collisions with a certain special initial geometry, e.g., a large ellipsoidal or triangular deformation, by classifying events by the value of their final observed flow coefficients. This procedure could be especially interesting for azimuthally dependent jet energy loss studies. We investigate the correlation between initial state features and final state momentum space anisotropies within an event-by-event hybrid approach. We find that the finite particle number and hadronic rescattering of the final state leads to large event-by-event fluctuations in the observables that could be used to characterize the features of the initial state. This makes event engineering by final state selection difficult. © 2013 American Physical Society.}, Doi = {10.1103/PhysRevC.88.044918}, Key = {fds247185} } @article{fds247186, Author = {Kirakosyan, M and Leonidov, A and Müller, B}, Title = {Turbulence-induced instabilities in EP and QGP}, Journal = {Acta Physica Polonica B, Proceedings Supplement}, Volume = {6}, Number = {2}, Pages = {403-408}, Year = {2013}, ISSN = {1899-2358}, url = {http://dx.doi.org/10.5506/APhysPolBSupp.6.403}, Abstract = {Polarization properties of turbulent stochastically inhomogeneous ultrarelativistic QED plasma are studied. It is shown that the sign of nonlinear turbulent Landau damping corresponds to an instability of the spacelike modes and, for sufficiently large turbulent fields, to an actual instability of a system.}, Doi = {10.5506/APhysPolBSupp.6.403}, Key = {fds247186} } @article{fds247189, Author = {Coleman-Smith, CE and Müller, B and Bass, SA}, Title = {Systematic Monte-Carlo studies of dijets at RHIC using the VNI/BMS Parton Cascade}, Journal = {Nuclear Physics A}, Volume = {904-905}, Pages = {759c-762c}, Year = {2013}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2013.02.128}, Abstract = {We present a study of the dijet suppression at RHIC using the parton cascade model. We examine the modification of the dijet asymmetry A j and the fragmentation distributions z and j T in terms of: q̂; the path length of leading and sub-leading jets; cuts on the jet energy distributions; jet cone angle and the jet-medium interaction mechanism. We have introduced a string hadronization model and present hadronic jet fragmentation distributions. We find that A j is most sensitive to q̂ and less sensitive to the nature of the jet-medium interaction mechanism. The fragmentation distributions show jet modification and differentiate between elastic and radiative+elastic modes. © 2013 Elsevier B.V.}, Doi = {10.1016/j.nuclphysa.2013.02.128}, Key = {fds247189} } @article{fds247193, Author = {Balasubramanian, V and Bernamonti, A and Craps, B and Keränen, V and Keski-Vakkuri, E and Müller, B and Thorlacius, L and Vanhoof, J}, Title = {Thermalization of the spectral function in strongly coupled two dimensional conformal field theories}, Journal = {Journal of High Energy Physics}, Volume = {2013}, Number = {4}, Pages = {069}, Year = {2013}, ISSN = {1126-6708}, url = {http://arXiv.org/pdf/1212.6066}, Abstract = {Using Wigner transforms of Green functions, we discuss non-equilibrium generalizations of spectral functions and occupation numbers. We develop methods for computing time-dependent spectral functions in conformal field theories holographically dual to thin-shell AdS-Vaidya spacetimes. © 2013 SISSA.}, Doi = {10.1007/JHEP04(2013)069}, Key = {fds247193} } @article{fds247195, Author = {Ayyar, V and Müller, B}, Title = {Approach to equilibrium in the caldeira-leggett model}, Journal = {International Journal of Modern Physics E}, Volume = {22}, Number = {3}, Pages = {1350016}, Year = {2013}, ISSN = {0218-3013}, url = {http://arxiv.org/pdf/1212.3538}, Abstract = {The Caldeira-Leggett (CL) model describes a microscopic quantum system, represented by a harmonic oscillator, in interaction with a heat bath, represented by a large number of harmonic oscillators with a range of frequencies. We consider the case when the system oscillator starts out in the ground state and then thermalizes due to interactions with the heat bath, which is at temperature θ. We calculate the position autocorrelation function 〈x(t')x(t)〉 of the system oscillator at two different times and study its behavior in the small and large time limits. Our results show that the system oscillator thermalizes as expected. We also confirm by explicit calculation that the position autocorrelation function exhibits periodicity for imaginary values of the time difference t'-t = iτ at late-(real) times t. © 2013 World Scientific Publishing Company.}, Doi = {10.1142/S021830131350016X}, Key = {fds247195} } @article{fds247196, Author = {Müller, B and Yang, D-L}, Title = {Light probes in a strongly coupled anisotropic plasma}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {87}, Number = {4}, Pages = {046004}, Year = {2013}, ISSN = {1550-7998}, url = {http://dx.doi.org/10.1103/PhysRevD.87.046004}, Abstract = {We employ the gauge/gravity duality to study the jet quenching of light probes traversing a static yet anisotropic strongly coupled N=4 super Yang-Mills plasma. We compute the stopping distance of an image jet induced by a massless source field, which is characterized by a massless particle falling along the null geodesic in the WKB approximation, in an anisotropic dual geometry introduced by Mateos and Trancancelli. At mid and large anisotropic regimes, the stopping distances of a probe traveling in the anisotropic plasma along various orientations are suppressed compared to those in an isotropic plasma, especially along the longitudinal direction at equal temperature. However, when fixing the entropy density, the anisotropic values of stopping distances near the transverse directions slightly surpass the isotropic values. In general, the jet quenching of light probes is increased by the anisotropic effect in a strongly coupled and equilibrium plasma. © 2013 American Physical Society.}, Doi = {10.1103/PhysRevD.87.046004}, Key = {fds247196} } @article{fds247274, Author = {Coleman-Smith, CE and Mueller, B}, Title = {Results of a systematic study of dijet suppression measured at the BNL Relativistic Heavy Ion Collider}, Journal = {Physical Review C}, Volume = {86}, Number = {5}, Pages = {054901}, Year = {2012}, Month = {November}, ISSN = {2469-9985}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000310685400007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Doi = {10.1103/PhysRevC.86.054901}, Key = {fds247274} } @article{fds247190, Author = {Cao, S and Qin, G-Y and Bass, SA and Mueller, B}, Title = {Collisional vs. Radiative Energy Loss of Heavy Quark in a Hot and Dense Nuclear Matter}, Journal = {Nuclear Physics A}, Year = {2012}, Month = {October}, url = {http://arxiv.org/abs/arXiv:1209.5410}, Key = {fds247190} } @article{fds247272, Author = {Asakawa, M and Bass, SA and Mueller, B}, Title = {Center Domains and their Phenomenological Consequences}, Journal = {Physical Review Letters}, Volume = {110}, Pages = {202301}, Year = {2012}, Month = {July}, url = {http://arxiv.org/abs/arXiv:1208.2426}, Abstract = {http://arxiv.org/abs/1208.2426}, Key = {fds247272} } @article{fds247183, Author = {Arnold, P and Florkowski, W and Fodor, Z and Foka, P and Harris, J and Lisa, M and Meyer, H and Milov, A and Mischke, A and Müller, B and al, E}, Title = {What is the quark-gluon plasma (QGP) and how do we find out?}, Journal = {PoS - Proceedings of Science}, Year = {2012}, ISSN = {1824-8039}, Abstract = {We present a panel discussion about our current state of knowledge about the Quark-Gluon Plasma. The nine panelists were asked to address the question: What do we want to know about the quark-gluon plasma, and how can we find the answers? The contributions illuminate our present understanding and highlight various aspects of the ongoing debate about the future directions of relativistic heavy-ion collision research. © Copyright owned by the author(s).}, Key = {fds247183} } @article{fds247194, Author = {Qin, G-Y and Müller, B}, Title = {Erratum: Explanation of dijet asymmetry in Pb-pb collisions at the large hadron collider (Physical Review Letters)}, Journal = {Physical Review Letters}, Volume = {108}, Number = {18}, Year = {2012}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.108.189904}, Doi = {10.1103/PhysRevLett.108.189904}, Key = {fds247194} } @article{fds247260, Author = {Coleman-Smith, CE and Qin, G-Y and Bass, SA and Müller, B}, Title = {Jet modification in a brick of QGP matter}, Journal = {AIP Conference Proceedings}, Volume = {1441}, Pages = {892-894}, Year = {2012}, ISSN = {0094-243X}, url = {http://dx.doi.org/10.1063/1.3700711}, Abstract = {We have implemented the LPM effect into a microscopic transport model with partonic degrees of freedom by following the algorithm of Zapp & Wiedemann. The Landau-Pomeranchuk-Migdal (LPM) effect is a quantum interference process that modifies the emission of radiation in the presence of a dense medium. In QCD this results in a quadratic length dependence for radiative energy loss. This is an important effect for the modification of jets by their passage through the QGP. We verify the leading parton energy loss in the model against the leading order Baier-Dokshitzer-Mueller-Peigne-Schiff-Zakharov (BDMPS-Z) result. We apply our model to the recent observations of the modification of di-jets at the LHC. © 2012 American Institute of Physics.}, Doi = {10.1063/1.3700711}, Key = {fds247260} } @article{fds247273, Author = {uuml, M and ller, B}, Title = {No Pain, no Gain: Hard probes of the quark-gluon plasma coming of age}, Journal = {Nucl. Phys. A}, Volume = {910}, Pages = {5}, Year = {2012}, url = {http://arxiv.org/pdf/1207.7302}, Abstract = {http://arxiv.org/abs/1207.7302}, Key = {fds247273} } @article{fds247275, Author = {Müller, B and Schukraft, J and Wysłouch, B}, Title = {First results from Pb+Pb collisions at the LHC}, Journal = {Annual Review of Nuclear and Particle Science}, Volume = {62}, Pages = {361-386}, Year = {2012}, ISSN = {0163-8998}, url = {http://arxiv.org/pdf/1202.3233v1.pdf}, Abstract = {At the end of 2010, the Large Hadron Collider (LHC) at CERN started operation with heavy-ion beams, colliding lead nuclei at a center-of-mass energy of 2.76 TeV per nucleon. These collisions ushered in a new era in ultrarelativistic heavy-ion physics at energies exceeding that of previous accelerators by more than an order of magnitude. This review summarizes the results from the first year of heavy-ion physics at the LHC obtained by the three experiments participating in the heavy-ion program: ALICE, ATLAS, and CMS. © 2012 by Annual Reviews.}, Doi = {10.1146/annurev-nucl-102711-094910}, Key = {fds247275} } @article{fds247277, Author = {Jacak, BV and Müller, B}, Title = {The exploration of hot nuclear matter}, Journal = {Science}, Volume = {337}, Number = {6092}, Pages = {310-314}, Year = {2012}, ISSN = {0036-8075}, url = {http://www.sciencemag.org/content/337/6092/310.full}, Abstract = {When nuclear matter is heated beyond 2 trillion degrees, it becomes a strongly coupled plasma of quarks and gluons. Experiments using highly energetic collisions between heavy nuclei have revealed that this new state of matter is a nearly ideal, highly opaque liquid. A description based on string theory and black holes in five dimensions has made the quark-gluon plasma an archetypical strongly coupled quantum system. Open questions about the structure and theory of the quark-gluon plasma are under active investigation. Many of the insights are also relevant to ultracold fermionic atoms and strongly correlated condensed matter.}, Doi = {10.1126/science.1215901}, Key = {fds247277} } @article{fds247278, Author = {Qin, G-Y and Müller, B}, Title = {Counting hot/cold spots in quark-gluon plasma}, Journal = {Physical Review C - Nuclear Physics}, Volume = {85}, Number = {6}, Pages = {061901(R)}, Year = {2012}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/1109.5961}, Abstract = {We study how local fluctuations in the initial states of relativistic heavy-ion collisions manifest in the correlations between different orders of harmonic moments of the density profiles, particularly those involving only odd harmonics that arise purely from initial-state fluctuations. We find the strengths of those correlations are sensitive to the number of hot and cold spots in the initial states. Hydrodynamic evolution of the fireball translates initial-state geometric anisotropies as well as their correlations into final-state momentum anisotropies and correlations. We conclude that the measurement of the correlations between different harmonic moments of final-state azimuthal distribution can be employed to quantify the inhomogeneity of the initial density profiles such as the population of hot and cold spots that are produced in high-energy nuclear collisions. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevC.85.061901}, Key = {fds247278} } @article{fds247279, Author = {M, and uuml, and ller, B and Sch, and auml, and fer, A}, Title = {Transverse energy density fluctuations in the color glass condensate model}, Journal = {Phys. Rev. D}, Volume = {85}, Number = {11}, Pages = {114030}, Year = {2012}, ISSN = {1550-7998}, url = {http://arxiv.org/pdf/arXiv:1111.3347}, Abstract = {http://arXiv.org/abs/arXiv:1111.3347}, Doi = {10.1103/PhysRevD.85.114030}, Key = {fds247279} } @article{fds247280, Author = {Kapusta, JI and Müller, B and Stephanov, M}, Title = {Relativistic theory of hydrodynamic fluctuations with applications to heavy-ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {85}, Number = {5}, Pages = {054906}, Year = {2012}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/1112.6405}, Abstract = {We develop the relativistic theory of hydrodynamic fluctuations for application to high-energy heavy-ion collisions. In particular, we investigate their effect on the expanding boost-invariant (Bjorken) solution of the hydrodynamic equations. We discover that correlations over a long rapidity range are induced by the propagation of the sound modes. Due to the expansion, the dispersion law for these modes is nonlinear and attenuated even in the limit of zero viscosity. As a result, there is a nondissipative wake behind the sound front which is generated by any instantaneous pointlike fluctuation. We evaluate the two-particle correlators using the initial conditions and hydrodynamic parameters relevant for heavy-ion collisions at RHIC and LHC. In principle these correlators can be used to obtain information about the viscosities because the magnitudes of the fluctuations are directly proportional to them. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevC.85.054906}, Key = {fds247280} } @article{fds247281, Author = {Kapusta, J and Müller, B and Stephanov, M}, Title = {Relativistic noise}, Journal = {Acta Physica Polonica, Series B.}, Volume = {43}, Number = {4}, Pages = {781-790}, Year = {2012}, ISSN = {0587-4254}, url = {http://th-www.if.uj.edu.pl/acta/vol43/pdf/v43p0781.pdf}, Abstract = {The relativistic theory of hydrodynamic fluctuations, or noise, is derived and applied to high energy heavy ion collisions. These fluctuations are inherent in any space-time varying system and are present in addition to initial state fluctuations. We illustrate the effects with the boost-invariant Bjorken solution to the hydrodynamic equations. Long range correlations in rapidity are induced by propagation of sound modes. The magnitude of these correlations is directly proportional to the viscosities. These fluctuations should be enhanced near a phase transition or rapid crossover.}, Doi = {10.5506/APhysPolB.43.781}, Key = {fds247281} } @article{fds247282, Author = {Müller, B}, Title = {Strangeness and the quark-gluon PLASMA: Thirty years of discovery}, Journal = {Acta Physica Polonica, Series B.}, Volume = {43}, Number = {4}, Pages = {761-770}, Year = {2012}, ISSN = {0587-4254}, url = {http://th-www.if.uj.edu.pl/acta/vol43/pdf/v43p0761.pdf}, Abstract = {I review the role of strange quarks as probes of hot QCD matter.}, Doi = {10.5506/APhysPolB.43.761}, Key = {fds247282} } @article{fds247283, Author = {Tsai, H-M and Müller, B}, Title = {Entropy production and equilibration in Yang-Mills quantum mechanics}, Journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics}, Volume = {85}, Number = {1}, Pages = {011110}, Year = {2012}, ISSN = {1539-3755}, url = {http://hdl.handle.net/10161/4970 Duke open access}, Abstract = {The Husimi distribution provides for a coarse-grained representation of the phase-space distribution of a quantum system, which may be used to track the growth of entropy of the system. We present a general and systematic method of solving the Husimi equation of motion for an isolated quantum system, and we construct a coarse-grained Hamiltonian whose expectation value is exactly conserved. As an application, we numerically solve the Husimi equation of motion for two-dimensional Yang-Mills quantum mechanics (the x-y model) and calculate the time evolution of the coarse-grained entropy of a highly excited state. We show that the coarse-grained entropy saturates to a value that coincides with the microcanonical entropy corresponding to the energy of the system. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevE.85.011110}, Key = {fds247283} } @article{fds247285, Author = {Yang, DL and uuml, M and ller, B}, Title = {J/Ψ production by magnetic excitation of ηc}, Journal = {J. Phys. G}, Volume = {39}, Number = {1}, Pages = {015007}, Year = {2012}, ISSN = {0954-3899}, url = {http://arxiv.org/pdf/1108.2525}, Abstract = {http://arxiv.org/abs/1108.2525}, Doi = {10.1088/0954-3899/39/1/015007}, Key = {fds247285} } @article{fds304597, Author = {Müller, B and Schäfer, A}, Title = {Transverse energy density fluctuations in heavy-ion collisions in a gaussian model}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {85}, Number = {11}, Year = {2012}, ISSN = {1550-7998}, url = {http://dx.doi.org/10.1103/PhysRevD.85.114030}, Abstract = {We calculate the transverse correlation of fluctuations of the deposited energy density in nuclear collisions in the framework of a Gaussian model similar to the color glass condensate model. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevD.85.114030}, Key = {fds304597} } @article{fds318458, Author = {Yang, D-L and Müller, B}, Title = {J/ψ production by magnetic excitation of η_{c}}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {39}, Number = {1}, Year = {2012}, url = {http://dx.doi.org/10.1088/0954-3899/39/1/015007}, Abstract = {We compute the probability of J/ production from the interaction between c and the strong magnetic field generated in relativistic heavy ion collisions. The computation is first carried out in the heavy quark effective model, in which the M1 radiative transition is considered. Then, we investigate the transition in the framework of non-relativistic heavy hadron chiral perturbation theory and show that the polarization of J/ produced by this process is parallel to the direction of magnetic field and thus perpendicular to the reaction plane. The transition probability obtained in both approaches is of order 2 × 104. © 2012 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/39/1/015007}, Key = {fds318458} } @article{fds247293, Author = {Stave, S and Ahmed, MW and III, FRH and Henshaw, SS and Muellner, B and Perdue, BA and Prior, RM and Spraker, MC and Weller, HR}, Title = {Understanding the B-11(p, alpha)alpha alpha reaction at the 0.675 MeV resonance}, Journal = {Physics Letters B}, Volume = {696}, Number = {1-2}, Pages = {26-29}, Year = {2011}, Month = {January}, ISSN = {0370-2693}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000286708900006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Doi = {10.1016/j.physletb.2010.12.015}, Key = {fds247293} } @article{fds247241, Author = {Stave, S and Ahmed, MW and France, RH and Henshaw, SS and Müller, B and Perdue, BA and Prior, RM and Spraker, MC and Weller, HR}, Title = {Understanding the B^{11}(p,α)αα reaction at the 0.675 MeV resonance}, Journal = {Physics Letters B}, Volume = {696}, Number = {1-2}, Pages = {26-29}, Year = {2011}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/j.physletb.2010.12.015}, Abstract = {The B11(p,α)αα reaction at energies between 200 keV and a few MeV has a very long history, dating back to studies by Lord Rutherford and Dee and Gilbert in the 1930s. It is shown that the modern view of this reaction, established in 1987, is incorrect. This model viewed the reaction as a two-step process with a primary high energy α-particle having ℓ=1 going to the first excited state of Be8, with the subsequent emission of two low energy secondary α-particles. We have found that an earlier result (1969) which showed that the primary α-particle must have ℓ=3 does, as originally noted, account for the data. Our simulations show that this view leads to the prediction of two high energy α-particles (of almost equal energy), as originally proposed in 1936, one being the primary α-particle and the other a secondary α-particle. Coincidence data verify the existence of these two high energy α-particles. The implications of this result on astrophysics and fusion energy production are noted. © 2010 Elsevier B.V.}, Doi = {10.1016/j.physletb.2010.12.015}, Key = {fds247241} } @article{fds247242, Author = {Qin, G-Y and Müller, B}, Title = {Explanation of dijet asymmetry in Pb-pb collisions at the large hadron collider}, Journal = {Physical Review Letters}, Volume = {106}, Number = {16}, Year = {2011}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.106.162302}, Abstract = {We investigate the medium modification of a partonic jet shower traversing in a hot quark-gluon plasma. We derive and solve a differential equation that governs the evolution of the radiated gluon distribution as the jet propagates through the medium. Energy contained inside the jet cone is lost by dissipation through elastic collisions with the medium and by scattering of shower partons to larger angles. We find that the jet energy loss at early times is dominated by medium effects on the vacuum radiation, and by medium-induced radiation effects at late times. We compare our numerical results for the nuclear modification of the dijet asymmetry with that recently reported by the ATLAS Collaboration. © 2011 American Physical Society.}, Doi = {10.1103/PhysRevLett.106.162302}, Key = {fds247242} } @article{fds247276, Author = {Armesto, N and Cole, B and Gale, C and Horowitz, WA and Jacobs, P and Jeon, S and van Leeuwen, M and Majumder, A and uuml, M and ller, B and Qin, GY}, Title = {Comparison of jet quenching formalisms for a quark-gluon plasma "brick"}, Journal = {Phys. Rev. C}, Volume = {86}, Pages = {064904}, Year = {2011}, url = {http://arxiv.org/pdf/1106.1106}, Abstract = {http://arxiv.org/abs/1106.1106}, Key = {fds247276} } @article{fds247284, Author = {Müller, B and SchÄfer, A}, Title = {Entropy creation in relativistic heavy ion collisions}, Journal = {International Journal of Modern Physics E}, Volume = {20}, Number = {11}, Pages = {2235-2267}, Year = {2011}, ISSN = {0218-3013}, url = {http://arxiv.org/pdf/1110.2378}, Abstract = {We review current ideas on entropy production during the different stages of a relativistic nuclear collision. This includes recent results on decoherence entropy and the entropy produced during the hydrodynamic phase by viscous effects. We start by a discussion of decoherence caused by gluon bremsstrahlung in the very first interactions of gluons from the colliding nuclei. We then present a general framework, based on the Husimi distribution function, for the calculation of entropy growth in quantum field theories, which is applicable to the early ("glasma") phase of the collision during which most of the entropy is generated. The entropy calculated from the Husimi distribution exhibits linear growth when the quantum field contains unstable modes and the growth rate is asymptotically equal to the KolmogorovSinaï entropy. We outline how the approach can be used to investigate the problem of entropy production in a relativistic heavy ion reaction from first principles. We show that the same result can be obtained in the framework of a completely different approach called eigenstate thermalization hypothesis. Finally we discuss some recent results on entropy production in the strong coupling limit, as obtained from AdS/CFT duality. © 2011 World Scientific Publishing Company.}, Doi = {10.1142/S0218301311020459}, Key = {fds247284} } @article{fds247286, Author = {Müller, B}, Title = {The limits of ordinary matter}, Journal = {Science}, Volume = {332}, Number = {6037}, Pages = {1513-1514}, Year = {2011}, ISSN = {0036-8075}, url = {http://dx.doi.org/10.1126/science.1207995}, Abstract = {The temperature at which quarks escape the confines of protons and neutrons has been determined from high-energy particle collision data.}, Doi = {10.1126/science.1207995}, Key = {fds247286} } @article{fds247287, Author = {Müller, B}, Title = {Parton energy loss in strongly coupled AdS/CFT}, Journal = {Nuclear Physics A}, Volume = {855}, Number = {1}, Pages = {74-82}, Year = {2011}, ISSN = {0375-9474}, url = {http://arXiv.org/pdf/1010.4258}, Abstract = {This is a brief review of the theory and phenomenology of parton energy loss in strongly coupled field theories with a gravity dual and its comparison with parton energy loss in QCD at weak coupling. © 2011 Elsevier B.V.}, Doi = {10.1016/j.nuclphysa.2011.02.022}, Key = {fds247287} } @article{fds247288, Author = {Asakawa, M and Bass, SA and Müller, B}, Title = {Anomalous transport processes in turbulent non-Abelian plasmas}, Journal = {Nuclear Physics A}, Volume = {854}, Number = {1}, Pages = {76-80}, Year = {2011}, ISSN = {0375-9474}, url = {http://arXiv.org/pdf/1008.3496}, Abstract = {Turbulent color fields, which can arise in the early and late stages of relativistic heavy ion collisions, may contribute significantly to the transport processes in the matter created in these collisions. We review the theory of these anomalous transport processes and discuss their possible phenomenology in the glasma and quasistationary expanding quark-gluon plasma. © 2010 Elsevier B.V.}, Doi = {10.1016/j.nuclphysa.2010.07.013}, Key = {fds247288} } @article{fds247289, Author = {Qin, GY and uuml, M and ller, B}, Title = {Di-jet asymmetry in Pb+Pb collisions at the Large Hadron Collide}, Journal = {Phys. Rev. Lett.}, Volume = {106}, Pages = {162302}, Year = {2011}, url = {http://arxiv.org/pdf/1012.5280}, Abstract = {http://arXiv.org/abs/1012.5280}, Key = {fds247289} } @article{fds247290, Author = {Balasubramanian, V and Bernamonti, A and Boer, JD and Copland, N and Craps, B and Keski-Vakkuri, E and Müller, B and Schäfer, A and Shigemori, M and Staessens, W}, Title = {Thermalization of strongly coupled field theories}, Journal = {Physical Review Letters}, Volume = {106}, Number = {19}, Pages = {191601}, Year = {2011}, ISSN = {0031-9007}, url = {http://arxiv.org/pdf/1012.4753}, Abstract = {Using the holographic mapping to a gravity dual, we calculate 2-point functions, Wilson loops, and entanglement entropy in strongly coupled field theories in d=2, 3, and 4 to probe the scale dependence of thermalization following a sudden injection of energy. For homogeneous initial conditions, the entanglement entropy thermalizes slowest and sets a time scale for equilibration that saturates a causality bound. The growth rate of entanglement entropy density is nearly volume-independent for small volumes but slows for larger volumes. In this setting, the UV thermalizes first. © 2011 American Physical Society.}, Doi = {10.1103/PhysRevLett.106.191601}, Key = {fds247290} } @article{fds247291, Author = {Balasubramanian, V and Bernamonti, A and Boer, JD and Copland, N and Craps, B and Keski-Vakkuri, E and Müller, B and Schäfer, A and Shigemori, M and Staessens, W}, Title = {Holographic thermalization}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {84}, Number = {2}, Pages = {026010}, Year = {2011}, ISSN = {1550-7998}, url = {http://arxiv.org/pdf/1103.2683}, Abstract = {Using the AdS/CFT correspondence, we probe the scale dependence of thermalization in strongly coupled field theories following a sudden injection of energy via calculations of two-point functions, Wilson loops, and entanglement entropy in d=2, 3, 4. In the saddle-point approximation these probes are computed in AdS space in terms of invariant geometric objects-geodesics, minimal surfaces, and minimal volumes. Our calculations for two-dimensional field theories are analytical. In our strongly coupled setting, all probes in all dimensions share certain universal features in their thermalization: (1) a slight delay in the onset of thermalization, (2) an apparent nonanalyticity at the endpoint of thermalization, (3) top-down thermalization where the UV thermalizes first. For homogeneous initial conditions the entanglement entropy thermalizes slowest and sets a timescale for equilibration that saturates a causality bound over the range of scales studied. The growth rate of entanglement entropy density is nearly volume-independent for small volumes, but slows for larger volumes. © 2011 American Physical Society.}, Doi = {10.1103/PhysRevD.84.026010}, Key = {fds247291} } @article{fds247292, Author = {Qin, G-Y and Petersen, H and Bass, SA and Müller, B}, Title = {Translation of collision geometry fluctuations into momentum anisotropies in relativistic heavy-ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {82}, Number = {6}, Pages = {064903}, Year = {2010}, ISSN = {0556-2813}, url = {http://arXiv.org/pdf/1009.1847}, Abstract = {We develop a systematic framework for the study of the initial collision geometry fluctuations in relativistic heavy-ion collisions and investigate how they evolve through different stages of the fireball history and translate into final-particle momentum anisotropies. We find in our event-by-event analysis that only the few lowest momentum anisotropy parameters survive after the hydrodynamical evolution of the system. The geometry of the produced medium is found to be affected by the pre-equilibrium evolution of the medium and the thermal smearing of the discretized event-by-event initial conditions, both of which tend to smear out the spatial anisotropies. We find such effects to be more prominent for higher moments than for lower moments. The correlations between odd and even spatial anisotropy parameters during the pre-equilibrium expansion are quantitatively studied and found to be small. Our study provides a theoretical foundation for the understanding of initial-state fluctuations and the collective expansion dynamics in relativistic heavy-ion collisions. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevC.82.064903}, Key = {fds247292} } @article{fds247294, Author = {Petersen, H and Qin, G-Y and Bass, SA and Müller, B}, Title = {Triangular flow in event-by-event ideal hydrodynamics in Au+Au collisions at √SNN = 200A GeV}, Journal = {Physical Review C - Nuclear Physics}, Volume = {82}, Number = {4}, Pages = {041901}, Year = {2010}, ISSN = {0556-2813}, url = {http://hdl.handle.net/10161/4268 Duke open access}, Abstract = {The first calculation of triangular flow ν3 in Au+Au collisions at √sNN = 200A GeV from an event-by-event (3 + 1) d transport+hydrodynamics hybrid approach is presented. As a response to the initial triangularity Ie{cyrillic, ukrainian}3 of the collision zone, ν3 is computed in a similar way to the standard event-plane analysis for elliptic flow ν2. It is found that the triangular flow exhibits weak centrality dependence and is roughly equal to elliptic flow in most central collisions. We also explore the transverse momentum and rapidity dependence of ν2 and ν3 for charged particles as well as identified particles. We conclude that an event-by-event treatment of the ideal hydrodynamic evolution startingwith realistic initial conditions generates the main features expected for triangular flow. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevC.82.041901}, Key = {fds247294} } @article{fds247295, Author = {Kunihiro, T and Müller, B and Ohnishi, A and Schäfer, A and Takahashi, TT and Yamamoto, A}, Title = {Chaotic behavior in classical Yang-Mills dynamics}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {82}, Number = {11}, Pages = {114015}, Year = {2010}, ISSN = {1550-7998}, url = {http://arXiv.org/pdf/1008.1156}, Abstract = {Understanding the underlying mechanisms causing rapid thermalization deduced for high-energy heavy ion collisions is still a challenge. To estimate the thermalization time, entropy growth for classical Yang-Mills theories is studied, based on the determination of Lyapunov exponents. Distinct regimes for short, medium and long sampling times are characterized by different properties of their spectrum of Lyapunov exponents. Clarifying the existence of these regimes and their implications for gauge-field dynamics is one of the results of this article. As a phenomenological application we conclude that for pure gauge theories with random initial conditions thermalization occurs within a few fm/c, an estimate which can be reduced by the inclusion of fermions, specific initial conditions, etc. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevD.82.114015}, Key = {fds247295} } @article{fds247296, Author = {Majumder, A and Müller, B}, Title = {Hadron mass spectrum from lattice QCD}, Journal = {Physical Review Letters}, Volume = {105}, Number = {25}, Pages = {252002}, Year = {2010}, ISSN = {0031-9007}, url = {http://arXiv.org/pdf/1008.1747}, Abstract = {Finite temperature lattice simulations of quantum chromodynamics (QCD) are sensitive to the hadronic mass spectrum for temperatures below the "critical" temperature Tc≈160MeV. We show that a recent precision determination of the QCD trace anomaly shows evidence for the existence of a large number of hadron states beyond those known from experiment. The lattice results are well represented by an exponentially growing mass spectrum up to a temperature T=155MeV. Using simple parametrizations of the hadron mass spectrum we show how one may estimate the total spectral weight in these yet undermined states. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevLett.105.252002}, Key = {fds247296} } @article{fds247297, Author = {Müller, B and Schäfer, A}, Title = {Charge fluctuations from the chiral magnetic effect in nuclear collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {82}, Number = {5}, Pages = {057902}, Year = {2010}, ISSN = {0556-2813}, url = {http://arXiv.org/pdf/1009.1053}, Abstract = {We derive a nonlocal effective Lagrangian for the chiral magnetic effect. An electric field is generated by winding number fluctuations of the nonabelian gauge field in the presence of a strong magnetic field. We estimate the magnitude of charge asymmetry fluctuations with respect to the reaction plane induced by the chiral magnetic effect in relativistic heavy-ion collisions to be less than 10⊃-6, several orders of magnitude smaller than the signal observed in the STAR experiment. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevC.82.057902}, Key = {fds247297} } @article{fds247298, Author = {Shin, GR and Bass, SA and Müller, B}, Title = {Transport theoretical description of collisional energy loss in infinite quark-gluon matter}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {37}, Number = {10}, Pages = {105112}, Year = {2010}, ISSN = {0954-3899}, url = {http://arXiv.org/pdf/1006.1668}, Abstract = {We study the time evolution of a high-momentum gluon or quark propagating through an infinite, thermalized, partonic medium utilizing a Boltzmann equation approach. We calculate the collisional energy loss of the parton, study its temperature and flavor dependence as well as the momentum broadening incurred through multiple interactions. Our transport calculations agree well with analytic calculations of collisional energy loss where available, but offer the unique opportunity to address the medium response as well in a consistent fashion. © 2010 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/37/10/105112}, Key = {fds247298} } @article{fds247299, Author = {Asakawa, M and Majumder, A and Müller, B}, Title = {Electric charge separation in strong transient magnetic fields}, Journal = {Physical Review C - Nuclear Physics}, Volume = {81}, Number = {6}, Pages = {064912}, Year = {2010}, ISSN = {0556-2813}, url = {http://hdl.handle.net/10161/4262 Duke open access}, Abstract = {We discuss various mechanisms for the creation of an asymmetric charge fluctuation with respect to the reaction plane among hadrons emitted in relativistic heavy-ion collisions. We show that such mechanisms exist in both the hadronic gas and the partonic phases of quantum chromodynamics. The mechanisms considered here all require the presence of a strong magnetic field (the "chiral magnetic effect"), but they do not involve parity or charge-parity violations. We analyze how a transient local electric current fluctuation generated by the chiral magnetic effect can dynamically evolve into an asymmetric charge distribution among final-state hadrons in momentum space. We estimate the magnitude of the event-by-event fluctuations of the final-state charge asymmetry owing to partonic and hadronic mechanisms. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevC.81.064912}, Key = {fds247299} } @article{fds247300, Author = {Mrówczyński, S and Müller, B}, Title = {Quasilinear transport approach to equilibration of quark-gluon plasmas}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {81}, Number = {6}, Pages = {065021}, Year = {2010}, ISSN = {1550-7998}, url = {http://hdl.handle.net/10161/4273 Duke open access}, Abstract = {We derive the transport equations of quark-gluon plasma in the quasilinear approximation. The equations are either of the Balescu-Lenard or Fokker-Planck form. The plasma's dynamics is assumed to be governed by longitudinal chromoelectric fields. The isotropic plasma, which is stable, and the two-stream system, which is unstable, are considered in detail. A process of equilibration is briefly discussed in both cases. The peaks of the two-stream distribution are shown to rapidly dissolve in time. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevD.81.065021}, Key = {fds247300} } @article{fds247180, Author = {Greiner, W and Müller, B}, Title = {Gauge theory of weak interactions}, Journal = {Gauge Theory of Weak Interactions}, Pages = {1-404}, Year = {2009}, Month = {December}, url = {http://dx.doi.org/10.1007/978-3-540-87843-8}, Abstract = {"Gauge Theory of Weak Interactions" treats the unification of electromagnetic and weak interactions and considers related phenomena. First, the Fermi theory of beta decay is presented, followed by a discussion of parity violation, clarifying the importance of symmetries. Then the concept of a spontaneously broken gauge theory is introduced, and all necessary mathematical tools are carefully developed. The "standard model" of unified electroweak interactions is thoroughly discussed including current developments. The final chapter contains an introduction to unified theories of strong and electroweak interactions. Numerous solved examples and problems make this volume uniquely suited as a text for an advanced course. This fourth edition has been carefully revised. © Springer-Verlag Berlin Heidelberg 2009 All rights are reserved.}, Doi = {10.1007/978-3-540-87843-8}, Key = {fds247180} } @article{fds324421, Author = {Asakawa, M and Bass, SA and Mueller, B and Nonaka, C}, Title = {Hydrodynamic Expansion with the QCD Critical Point(Thermal Quantum Field Theories and Their Applications)}, Volume = {116}, Number = {6}, Pages = {F36-F38}, Publisher = {Soryushiron Kenkyu}, Year = {2009}, Month = {February}, Abstract = {The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the μ_B-T phase diagram. If the average emission time of hadrons is a function of transverse velocity, as microscopic simulations of the hadronic freezeout dynamics suggest, the deformation of the hydrodynamic trajectories will change the transverse velocity (β_T) dependence of the proton-antiproton ratio when the fireball passes in the vicinity of the critical point. An unusual β_T-dependence of the p^^-/p ratio in a narrow beam energy window would thus signal the presence of the critical point.}, Key = {fds324421} } @article{fds247239, Author = {Tsai, H-M and Müller, B}, Title = {Aspects of thermal strange quark production: the deconfinement and chiral phase transitions}, Journal = {Nuclear Physics A}, Volume = {830}, Number = {1-4}, Pages = {551c-554c}, Year = {2009}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2009.09.045}, Abstract = {We study the gluonic sector of the three-flavor PNJL model by obtaining the adjoint Polyakov loop and the gluon distribution function in the mean-field approximation. Besides, we explore the thermal strange quark pair-production processes, q over(q, -) → s over(s, -) and g g → s over(s, -), with the aid of the three-flavor PNJL model. The results help us identify the temperature where the gluonic contribution to the production rate becomes dominant, which is an innovative phenomenon compared with the result obtained in free perturbation theory. © 2009 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2009.09.045}, Key = {fds247239} } @article{fds247240, Author = {Neufeld, RB and Müller, B}, Title = {The sound generated by a fast parton in the quark-gluon plasma is a crescendo}, Journal = {Nuclear Physics A}, Volume = {830}, Number = {1-4}, Pages = {789c-792c}, Year = {2009}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2009.10.072}, Abstract = {The total energy deposited into the medium per unit length by a fast parton traversing a quarkgluon plasma is calculated. We take the medium excitation due to collisions to be given by the well known expression for the collisional drag force. The parton's radiative energy loss contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. In our model, this leads to a length dependence on the differential energy loss due to the interactions of radiated gluons with the medium. The final result, which is a sum of the primary and the secondary contributions, is then treated as the coefficient of a local hydrodynamic source term. Results are presented for energy density wave induced by two fast, back-to-back partons created in an initial hard interaction. © 2009 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2009.10.072}, Key = {fds247240} } @article{fds247258, Author = {Lee, KS and Bass, S and Müller, B and Nonaka, C}, Title = {Hadronization via recombination}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {36}, Number = {6}, Year = {2009}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/36/6/064034}, Abstract = {The recombination model as a model for hadronization from a quark-gluon plasma has been recently revived since it has advantages in explaining several important features of the final state produced in heavy-ion collisions at the RHIC, such as the constituent quark number scaling of the elliptic coefficient versus the transverse energy of identified hadrons, the bending shape of the pT spectrum of hadrons near 5 GeV/c, and the measured large value of baryon-to-meson ratio (of the order of unity) in the same pT range. We have developed a dynamic simulation model of heavy-ion collisions in which a quark-gluon plasma, starting from a certain initial condition, evolves hydrodynamically until it reaches the phase boundary, and then hadronizes by valence quark recombination. Rescattering after hadronization is described by UrQMD. We discuss some details of the model and report first, preliminary results. © 2009 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/36/6/064034}, Key = {fds247258} } @article{fds247259, Author = {Nonaka, C and Asakawa, M and Bass, SA and Müller, B}, Title = {Signals of the QCD Critical Point in Hydrodynamic Evolutions}, Journal = {Nuclear Physics A}, Volume = {830}, Number = {1-4}, Pages = {291c-294c}, Year = {2009}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2009.10.025}, Abstract = {The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the μB - T phase diagram. The deformation of the hydrodynamic trajectories will change the transverse velocity (βT) dependence of the proton-antiproton ratio when the fireball passes in the vicinity of the critical point. An unusual βT dependence of the over(p, -) / p ratio in a narrow beam energy window would thus signal the presence of the critical point. © 2009.}, Doi = {10.1016/j.nuclphysa.2009.10.025}, Key = {fds247259} } @article{fds247301, Author = {uuml, M and ller, B}, Title = {Viewpoint: Looking for parity violation in heavy-ion collisions}, Journal = {Physics}, Volume = {2}, Pages = {104}, Year = {2009}, url = {http://physics.aps.org/articles/v2/104}, Key = {fds247301} } @article{fds247302, Author = {Majumder, A and Müller, B and Mrówczyński, S}, Title = {Momentum broadening of a fast parton in a perturbative quark-gluon plasma}, Journal = {Physical Review D - Particles, Fields, Gravitation, and Cosmology}, Volume = {80}, Number = {12}, Pages = {125020}, Year = {2009}, ISSN = {1550-7998}, url = {http://hdl.handle.net/10161/4270 Duke open access}, Abstract = {The average transverse momentum transfer per unit path length to a fast parton scattering elastically in a perturbative quark-gluon plasma is related to the radiative energy loss of the parton. We first calculate the momentum transfer coefficient q^ in terms of a classical Langevin problem and then define it quantum mechanically through a scattering matrix element. After treating the well-known case of a quark-gluon plasma in equilibrium, we consider an off-equilibrium unstable plasma. As a specific example, we treat the two-stream plasma with unstable modes of longitudinal chromoelectric field. In the presence of the instabilities, q^ is shown to exponentially grow in time. © 2009 The American Physical Society.}, Doi = {10.1103/PhysRevD.80.125020}, Key = {fds247302} } @article{fds247303, Author = {Fries, RJ and Kunihiro, T and Müller, B and Ohnishi, A and Schäfer, A}, Title = {From 0 to 5000 in 2 × 10^{-24}seconds: Entropy production in relativistic heavy-ion collisions}, Journal = {Nuclear Physics A}, Volume = {830}, Number = {1-4}, Pages = {519c-522c}, Year = {2009}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2009.09.041}, Abstract = {We review what is known about the contributions to the final entropy from the different stages of a relativistic nuclear collision, including recent results on the decoherence entropy and the entropy produced during the hydrodynamic phase by viscous effects. We then present a general framework, based on the Husimi distribution function, for the calculation of entropy growth in quantum field theories, which is applicable to the earliest ("glasma") phase of the collision during which most of the entropy is generated. The entropy calculated from the Husimi distribution exhibits linear growth when the quantum field contains unstable modes and is asymptotically equal to the Kolmogorov-Sinaï (KS) entropy. We outline how the approach can be used to investigate the problem of entropy production in a relativistic heavy-ion reaction from first principles. © 2009 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2009.09.041}, Key = {fds247303} } @article{fds247304, Author = {Neufeld, RB and Müller, B}, Title = {Sound Produced by a Fast Parton in the Quark-Gluon Plasma is a "crescendo"}, Journal = {Physical Review Letters}, Volume = {103}, Number = {4}, Pages = {042301}, Year = {2009}, ISSN = {0031-9007}, url = {http://arXiv.org/pdf/0902.2950}, Abstract = {We calculate the total energy deposited into the medium per unit length by fast partons traversing a quark-gluon plasma. The medium excitation due to collisions is taken to be given by the well-known expression for the collisional drag force. The radiative energy loss of the parton contributes to the energy deposition because each radiated gluon acts as an additional source of collisional energy loss in the medium. We derive a differential equation which governs how the spectrum of radiated gluons is modified when this energy loss is taken into account. This modified spectrum is then used to calculate the additional energy deposition due to the interactions of radiated gluons with the medium. Numerical results are presented for the medium response for the case of two energetic back-to-back partons created in a hard interaction. © 2009 The American Physical Society.}, Doi = {10.1103/PhysRevLett.103.042301}, Key = {fds247304} } @article{fds247306, Author = {Tsai, H-M and Müller, B}, Title = {Phenomenology of the three-flavor PNJL model and thermal strange quark production}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {36}, Number = {7}, Pages = {075101}, Year = {2009}, ISSN = {0954-3899}, url = {http://arxiv.org/pdf/0811.2216}, Abstract = {We study the temperature dependence of the adjoint Polyakov loop and its implication for the momentum spectrum of gluons in the mean-field approximation. This allows us to calculate the contribution of the thermal (transverse) gluons to the thermodynamic pressure. As an application, we evaluate the rates for the strange quark pair-production processes and as functions of temperature including thermal effects on quark deconfinement and chiral symmetry breaking. © 2009 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/36/7/075101}, Key = {fds247306} } @article{fds247307, Author = {Fries, RJ and Müller, B and Schäfer, A}, Title = {Decoherence and entropy production in relativistic nuclear collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {79}, Number = {3}, Pages = {034904}, Year = {2009}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.79.034904}, Abstract = {Short thermalization times of less than 1 fm/c for quark and gluon matter have been suggested by recent experiments at the Relativistic Heavy Ion Collider. It has been difficult to justify this rapid thermalization in first-principle calculations based on perturbation theory or the color glass condensate picture. Here, we address the related question of the decoherence of the gluon field, which is a necessary component of thermalization. We present a simplified leading-order computation of the decoherence time of a gluon ensemble subject to an incoming flux of Weizsäcker-Williams gluons. We also discuss the entropy produced during the decoherence process and its relation to the entropy in the final state that has been measured experimentally. © 2009 The American Physical Society.}, Doi = {10.1103/PhysRevC.79.034904}, Key = {fds247307} } @article{fds247308, Author = {Kunihiro, T and Müller, B and Ohnishi, A and Schäfer, A}, Title = {Towards a theory of entropy production in the little and big bang}, Journal = {Progress of Theoretical Physics}, Volume = {121}, Number = {3}, Pages = {555-575}, Year = {2009}, ISSN = {0033-068X}, url = {http://ptp.ipap.jp/link?PTP/121/555}, Abstract = {We propose a broadly applicable formalism for the description of coarse grained entropy production in quantum mechanical processes. Our formalism is based on the Husimi transform of the quantum state, which encodes the notion that information about any quantum state is limited by the experimental resolution. We show in two analytically tractable cases (the decay of an unstable vacuum state and reheating after cosmic inflation) that the growth rate of the Wehrl entropy associated with the Husimi function approaches the classical Kolmogorov-Sinai' entropy. We also discuss various possible applications of our formalism, including the production of entropy in the early stages of a relativistic heavy ion collision.}, Doi = {10.1143/PTP.121.555}, Key = {fds247308} } @article{fds247309, Author = {Müller, B}, Title = {The "perfect" fluid quenches jets almost perfectly}, Journal = {Progress in Particle and Nuclear Physics}, Volume = {62}, Number = {2}, Pages = {551-555}, Year = {2009}, ISSN = {0146-6410}, url = {http://dx.doi.org/10.1016/j.ppnp.2008.12.028}, Abstract = {The QCD matter produced in nuclear collisions at the Relativistic Heavy Ion Collider (RHIC) has been found to have a very low shear viscosity, which is close to the lower bound allowed by unitarity. The matter has also been found to strongly suppress the emission of energetic hadrons. This phenomenon, called "jet quenching" is interpreted to be the result of a large energy loss by the precursor parton on its path through the dense matter, primarily due to gluon radiation. I discuss how the two phenomena are related. The RHIC data suggest, in some scenarios of jet quenching, that the quark-gluon plasma created in nuclear collisions is characterized by strong coupling, but still admits a quasi-particle description. © 2009 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.ppnp.2008.12.028}, Key = {fds247309} } @article{fds287694, Author = {Müller, B}, Title = {The flavours of the quark-gluon plasma}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {36}, Number = {6}, Year = {2009}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/36/6/064001}, Abstract = {Quarks of other flavours than up and down, i.e. s, c and b quarks, have been long recognized as effective probes of the structure of hot QCD matter. In this paper, I review some of the motivations for their investigation and discuss the salient results obtained so far, with a focus on the results from the Relativistic Heavy-Ion Collider (RHIC). Some ideas for future studies are also mentioned. © 2009 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/36/6/064001}, Key = {fds287694} } @article{fds182766, Author = {Kitazawa, M. and Asakawa, M. and Müller, B. and Nonaka, C.}, Title = {Measurement of shear viscosity in lattice gauge theory without Kubo formula}, Journal = {PoS LATTICE2008}, Pages = {183}, Year = {2008}, url = {http://pos.sissa.it//archive/conferences/066/183/LATTICE}, Key = {fds182766} } @article{Majumder:2007ne, Author = {Majumder, A and Fries, RJ and Müller, B}, Title = {Photon bremsstrahlung and diffusive broadening of a hard jet}, Journal = {Physical Review C - Nuclear Physics}, Volume = {77}, Number = {6}, Pages = {065209}, Year = {2008}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/arXiv:0711.2475 [nucl-th]}, Abstract = {The photon bremsstrahlung rate from a quark jet produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. The leading medium-enhanced higher twist corrections that describe the multiple scattering of the jet in the nucleus are re-summed to all orders of twist. The propagation of the jet in the absence of further radiative energy loss is shown to be governed by a transverse momentum diffusion equation. We compute the final photon spectrum in the limit of soft photons, taking into account the leading and next-to-leading terms in the photon momentum fraction y. In this limit, the photon spectrum in a physical gauge is shown to arise from two interfering sources: one where the initial hard scattering produces an off-shell quark, which immediately radiates the photon and then undergoes subsequent soft rescattering, and an alternative in which the quark is produced on-shell and propagates through the medium until it is driven off-shell by rescattering and radiates the photon. Our result has a simple formal structure as a product of the photon splitting function, the quark transverse momentum distribution coming from a diffusion equation, and a dimensionless factor that encodes the effect of the interferences encountered by the propagating quark over the length of the medium. The destructive nature of such interferences in the small-y limit is responsible for the origin of the Landau-Pomeranchuck-Migdal (LPM) effect. Along the way we also discuss possible implications for quark jets in hot nuclear matter. © 2008 The American Physical Society.}, Doi = {10.1103/PhysRevC.77.065209}, Key = {Majumder:2007ne} } @article{Majumder:2007hx, Author = {Majumder, A and Müller, B}, Title = {Higher twist jet broadening and classical propagation}, Journal = {Physical Review C - Nuclear Physics}, Volume = {77}, Number = {5}, Pages = {054903}, Year = {2008}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/arXiv:0705.1147 [nucl-th]}, Abstract = {The transverse broadening of jets produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. A class of medium enhanced higher twist corrections are resummed to calculate the transverse momentum distribution of the produced collinear jet. In contrast to previous approaches, resummation of the leading length enhanced higher twist corrections is shown to lead to a two-dimensional diffusion equation for the transverse momentum of the propagating jet. Results for the average transverse momentum obtained from this approach are then compared to the broadening expected from a classical Langevin analysis for the propagation of the jet under the action of the fluctuating color Lorentz force inside the nucleons. The set of approximations that lead to identical results from the two approaches are outlined. The relationship between the momentum diffusion constant D and the transport coefficient q^ is explicitly derived. © 2008 The American Physical Society.}, Doi = {10.1103/PhysRevC.77.054903}, Key = {Majumder:2007hx} } @article{fds247236, Author = {Müller, B}, Title = {Theoretical challenges posed by the data from RHIC}, Journal = {Progress of Theoretical Physics Supplement}, Number = {174}, Pages = {103-121}, Year = {2008}, ISSN = {0375-9687}, Abstract = {In this lecture, I discuss how the RHIC data are challenging our theoretical understanding of QCD matter. Important components of this challenge include how equilibrated QCD matter is formed, whether its statistical and dynamical properties permit a quasi-particle description, and what its transport properties are.}, Key = {fds247236} } @article{fds247237, Author = {Müller, B and Neufeld, RB}, Title = {The sound of a fast parton in QCD}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {35}, Number = {10}, Year = {2008}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/35/10/104108}, Abstract = {The spacetime distribution of energy and momentum deposited by a fast parton traversing a weakly coupled quark-gluon plasma is calculated by treating the fast parton as the source of an external color field perturbing the medium. When the result is used as a source term in the linearized hydrodynamical equations of the medium, the solution is found to contain a sonic Mach cone and a dissipative wake if the parton moves at supersonic speed. © 2008 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/35/10/104108}, Key = {fds247237} } @article{fds247310, Author = {Neufeld, RB and Müller, B and Ruppert, J}, Title = {Sonic Mach cones induced by fast partons in a perturbative quark-gluon plasma}, Journal = {Physical Review C - Nuclear Physics}, Volume = {78}, Number = {4}, Pages = {041901}, Year = {2008}, ISSN = {0556-2813}, url = {http://arXiv.org/pdf/0802.2254}, Abstract = {We derive the space-time distribution of energy and momentum deposited by a fast parton traversing a weakly coupled quark-gluon plasma by treating the fast parton as the source of an external color field perturbing the medium. We then use our result as a source term for the linearized hydrodynamical equations of the medium. We show that the solution contains a sonic Mach cone and a dissipative wake if the parton moves at a supersonic speed. © 2008 The American Physical Society.}, Doi = {10.1103/PhysRevC.78.041901}, Key = {fds247310} } @article{fds247311, Author = {Asakawa, M and Bass, SA and Müller, B and Nonaka, C}, Title = {Transverse velocity dependence of the proton-antiproton ratio as a signature of the QCD critical point}, Journal = {Physical Review Letters}, Volume = {101}, Number = {12}, Pages = {122302}, Year = {2008}, ISSN = {0031-9007}, url = {http://arXiv.org/pdf/0803.2449}, Abstract = {The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the μB-T phase diagram. If the average emission time of hadrons is a function of transverse velocity, as microscopic simulations of the hadronic freeze-out dynamics suggest, the deformation of the hydrodynamic trajectories will change the transverse velocity (βT) dependence of the proton-antiproton ratio when the fireball passes in the vicinity of the critical point. An unusual βT dependence of the p̄/p ratio in a narrow beam energy window would thus signal the presence of the critical point. © 2008 The American Physical Society.}, Doi = {10.1103/PhysRevLett.101.122302}, Key = {fds247311} } @article{fds247312, Author = {Fries, RJ and Müller, B and Schäfer, A}, Title = {Stress tensor and bulk viscosity in relativistic nuclear collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {78}, Number = {3}, Pages = {034913}, Year = {2008}, ISSN = {0556-2813}, url = {http://arXiv.org/pdf/0807.4333v2}, Abstract = {We discuss the influence of different initial conditions for the stress tensor and the effect of bulk viscosity on the expansion and cooling of the fireball created in relativistic heavy ion collisions. In particular, we explore the evolution of longitudinal and transverse components of the pressure and the extent of dissipative entropy production in the one-dimensional, boost-invariant hydrodynamic model. We find that a bulk viscosity consistent with recent estimates from lattice QCD further slows the equilibration of the system; however, it does not significantly increase the entropy produced. © 2008 The American Physical Society.}, Doi = {10.1103/PhysRevC.78.034913}, Key = {fds247312} } @article{fds247317, Author = {Majumder, A and Müller, B and Bass, SA}, Title = {Longitudinal broadening of quenched jets in turbulent color fields.}, Journal = {Physical Review Letters}, Volume = {99}, Number = {4}, Pages = {042301}, Year = {2007}, Month = {July}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17678353}, Abstract = {The nearside distribution of particles at intermediate transverse momentum, associated with a high momentum trigger hadron produced in a high energy heavy-ion collision, is broadened in rapidity compared with the jet cone. This broadened distribution is thought to contain the energy lost by the progenitor parton of the trigger hadron. We show that the broadening can be explained as the final-state deflection of the gluons radiated from the hard parton inside the medium by soft, transversely oriented, turbulent color fields that arise in the presence of plasma instabilities. The magnitude of the effect is found to grow with medium size and density and diminish with increasing energy of the associated hadron.}, Doi = {10.1103/PhysRevLett.99.042301}, Key = {fds247317} } @article{Muller:2007rs, Author = {Müller, B}, Title = {From quark-gluon plasma to the perfect liquid}, Journal = {Acta Physica Polonica, Series B.}, Volume = {38}, Number = {12}, Pages = {3705-3729}, Year = {2007}, ISSN = {0587-4254}, url = {http://arxiv.org/pdf/arXiv:0710.3366 [nucl-th]}, Abstract = {After reviewing some basic concepts of the theory of strongly interacting matter above nuclear energy density and reviewing some salient results of the experimental program at the Relativistic Heavy Ion Collider (RHIC), these lectures explain why the quark-gluon plasma observed in the RHIC experiments has been called a "perfect liquid" They then give an introduction to some recent ideas concerning the possible origin of the nearly inviscid nature of the quark-gluon plasma and discuss the connection between low viscosity and strong parton energy loss of hot QCD matter.}, Key = {Muller:2007rs} } @article{Majumder:2007zh, Author = {Majumder, A and Müller, B and Wang, X-N}, Title = {Small shear viscosity of a quark-gluon plasma implies strong jet quenching}, Journal = {Physical Review Letters}, Volume = {99}, Number = {19}, Pages = {192301}, Year = {2007}, ISSN = {0031-9007}, url = {http://arxiv.org/pdf/hep-ph/0703082}, Abstract = {We derive an expression relating the transport parameter q and the shear viscosity η of a weakly coupled quark-gluon plasma. A deviation from this relation can be regarded as a quantitative measure of "strong coupling" of the medium. The ratio T3/q, where T is the temperature, is a more broadly valid measure of the coupling strength of the medium than η/s, where s denotes the entropy density. Different estimates of q derived from existing Relativistic Heavy Ion Collider data are shown to imply radically different structures of the produced matter. © 2007 The American Physical Society.}, Doi = {10.1103/PhysRevLett.99.192301}, Key = {Majumder:2007zh} } @article{fds247235, Author = {Müller, B}, Title = {Hard Probes at LHC}, Journal = {Nuclear Physics A}, Volume = {783}, Number = {1-4 SPEC. ISS.}, Pages = {403-416}, Year = {2007}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2006.11.091}, Abstract = {This talk gives a theoretical perspective of the physics issues awaiting us when heavy ions will collide in the LHC. © 2006 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2006.11.091}, Key = {fds247235} } @article{fds247232, Author = {Ruppert, J and Renk, T and Müller, B}, Title = {Mass and width of the ρ-meson in a nuclear medium from Brown-Rho scaling and QCD sum rules}, Journal = {Physical Review C - Nuclear Physics}, Volume = {73}, Number = {3}, Year = {2006}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.73.034907}, Abstract = {We explore the range of values of the in-medium width of a ρ-meson at rest which is compatibale with the QCD sum rule approach in a nuclear medium assuming vector meson dominance and a Brown-Rho scaling law of the ρ-meson mass with the chiral condensate. The lower and upper bounds for the in-medium width are found to be strongly increasing with the decreasing mass of the ρ-meson (increasing nuclear density). We also study the bounds for the in-medium width in models not satisfying the Brown-Rho scaling law. It is shown that the in-medium width depends on how rapidly the mass decreases in comparison to the change of the quark condensate. The bounds for the in-medium width increase with density only if the relative change of the quark condensate is stronger than the relative decrease in mass. This is important for experimental tests of the Brown-Rho scaling paradigm and other dropping ρ-mass scenarios. © 2006 The American Physical Society.}, Doi = {10.1103/PhysRevC.73.034907}, Key = {fds247232} } @article{fds247256, Author = {Bass, SA and Fries, RJ and Müller, B}, Title = {Correlations in the Parton Recombination Model}, Journal = {Nuclear Physics A}, Volume = {774}, Number = {1-4}, Pages = {635-638}, Year = {2006}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2006.06.103}, Abstract = {We describe how parton recombination can address the recent measurement of dynamical jet-like two particle correlations. In addition we discuss the possible effect realistic light-cone wave-functions including higher Fock-states may have on the well-known elliptic flow valence-quark number scaling law. © 2006 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2006.06.103}, Key = {fds247256} } @article{fds247305, Author = {Asakawa, M and Bass, SA and Müller, B}, Title = {The flavours of the quark-gluon plasma}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {32}, Number = {12}, Pages = {064001}, Year = {2006}, ISSN = {0954-3899}, url = {http://arXiv.org/pdf/0812.4638}, Abstract = {Flavour probes depend on the transport properties of the quark-gluon plasma. An expanding quark-gluon plasma has an anomalous viscosity, which arises from interactions with dynamically generated colour fields. The anomalous viscosity dominates over the collisional viscosity for weak coupling and at not too late times. In addition to possibly providing an explanation for the apparent nearly 'perfect' liquidity of the matter produced in nuclear collisions at RHIC, similar anomalous effects can affect the rate of flavour equilibration and the diffusion constant of heavy quarks. © 2006 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/32/12/S50}, Key = {fds247305} } @article{fds247318, Author = {Asakawa, M and Bass, SA and Müller, B}, Title = {Anomalous transport processes in anisotropically expanding quark-gluon plasmas}, Journal = {Progress of Theoretical Physics}, Volume = {116}, Number = {4}, Pages = {725-755}, Year = {2006}, ISSN = {0033-068X}, url = {http://arxiv.org/pdf/hep-ph/0608270}, Abstract = {We derive an expression for the anomalous viscosity in an anisotropically expanding quark-gluon-plasma, which arises from interactions of thermal partons with dynamically generated color fields. The anomalous viscosity dominates over the collisional viscosity for large velocity gradients or weak coupling. This effect may provide an explanation for the apparent "nearly perfect" liquidity of the matter produced in nuclear collisions at RHIC without the assumption that it is a strongly coupled state.}, Doi = {10.1143/PTP.116.725}, Key = {fds247318} } @article{fds247319, Author = {Kanada-En'yo, Y and Müller, B}, Title = {Suppression of p-wave baryons in quark recombination}, Journal = {Physical Review C - Nuclear Physics}, Volume = {74}, Number = {6}, Pages = {061901}, Year = {2006}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/nucl-th/0608015}, Abstract = {We show that the observed suppression of the Λ(1520)/Λ ratio in central Au+Au collisions at the BNL Relativistic Heavy Ion Collider can be naturally understood in the constituent quark recombination model. © 2006 The American Physical Society.}, Doi = {10.1103/PhysRevC.74.061901}, Key = {fds247319} } @article{fds247320, Author = {Müller, B}, Title = {Quark Matter 2005 - Theoretical Summary}, Journal = {Nuclear Physics A}, Volume = {774}, Number = {1-4}, Pages = {433-453}, Year = {2006}, ISSN = {0375-9474}, url = {http://arxiv.org/pdf/nucl-th/0508062.pdf}, Abstract = {This is a review of the latest developments in the theory of superdense nuclear matter, formed in relativistic heavy ion collisions or in the core of collapsed stars, as they were reported and discussed at the Quark Matter 2005 conference in Budapest (Hungary). © 2006 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2006.06.063}, Key = {fds247320} } @article{fds247321, Author = {Majumder, A and Müller, B}, Title = {Baryonic strangeness and related susceptibilities in QCD}, Journal = {Physical Review C - Nuclear Physics}, Volume = {74}, Number = {5}, Pages = {054901}, Year = {2006}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/nucl-th/0605079}, Abstract = {The ratios of off-diagonal to diagonal conserved charge susceptibilities, e.g., χBS/χS,χQS/χS, related to the quark flavor susceptibilities, have proven to be discerning probes of the flavor carrying degrees of freedom in hot strongly interacting matter. Various constraining relations between the different susceptibilities are derived based on the Gell-Mann-Nishijima formula and the assumption of isospin symmetry. Using generic models of deconfined matter and results from lattice quantum chromodynamics, it is demonstrated that the flavor-carrying degrees of freedom at a temperature above 1.5Tc are quarklike quasiparticles. A new observable related by isospin symmetry to CBS=-3χBS/χS and equal to it in the baryon free regime is identified. This new observable, which is blind to neutral and nonstrange particles, carries the potential of being measured in relativistic heavy-ion collisions. © 2006 The American Physical Society.}, Doi = {10.1103/PhysRevC.74.054901}, Key = {fds247321} } @article{fds247324, Author = {Matinyan, SG and Müller, B}, Title = {The partition function in the Wigner-Kirkwood expansion}, Journal = {Journal of Physics A: Mathematical and General}, Volume = {39}, Number = {18}, Pages = {L285-L292}, Year = {2006}, ISSN = {0305-4470}, url = {http://arxiv.org/pdf/quant-ph/0602041.pdf}, Abstract = {We study the semiclassical Wigner-Kirkwood (WK) expansion of the partition function Z(t) for arbitrary even homogeneous potentials, starting from the Bloch equation. As is well known, the phase-space kernel of Z satisfies the so-called Uhlenbeck-Beth equation, which depends on the gradients of the potential. We perform a chain of transformations to obtain novel forms of this equation that invite analogies with various physical phenomena and formalisms, such as diffusion processes, the Fokker-Planck equation and supersymmetric quantum mechanics. © 2006 IOP Publishing Ltd.}, Doi = {10.1088/0305-4470/39/18/L05}, Key = {fds247324} } @article{fds247325, Author = {Müller, B and Nagle, JL}, Title = {REsults from the relativistic heavy ion collider}, Journal = {Annual Review of Nuclear and Particle Science}, Volume = {56}, Pages = {93-135}, Year = {2006}, ISSN = {0163-8998}, url = {http://arxiv.org/pdf/nucl-th/0602029.pdf}, Abstract = {This review describes the current status of the heavy ion research program at the Relativistic Heavy Ion Collider (RHIC). The new suite of experiments and the collider energies have opened up new probes of the medium created in the collisions. Our review focuses on the experimental discoveries to date at RHIC and their interpretation in light of the field's present theoretical understanding of the dynamics of relativistic heavy ion collisions and of the structure of strongly interacting matter at high energy density. Copyright © 2006 by Annual Reviews. All rights reserved.}, Doi = {10.1146/annurev.nucl.56.080805.140556}, Key = {fds247325} } @article{fds247326, Author = {Asakawa, M and Bass, SA and Müller, B}, Title = {Anomalous viscosity of an expanding quark-gluon plasma}, Journal = {Physical Review Letters}, Volume = {96}, Number = {25}, Pages = {S839-S842}, Year = {2006}, ISSN = {0031-9007}, url = {http://arxiv.org/pdf/hep-ph/0603092.pdf}, Abstract = {We argue that an expanding quark-gluon plasma has an anomalous viscosity, which arises from interactions with dynamically generated color fields. We derive an expression for the anomalous viscosity in the turbulent plasma domain and apply it to the hydrodynamic expansion phase, when the quark-gluon plasma is near equilibrium. The anomalous viscosity dominates over the collisional viscosity for weak coupling and not too late times. This effect may provide an explanation for the apparent â€œnearly perfectâ€ liquidity of the matter produced in nuclear collisions at the Relativistic Heavy Ion Collider without the assumption that it is a strongly coupled state. © 2006 The American Physical Society.}, Doi = {10.1103/PhysRevLett.96.252301}, Key = {fds247326} } @article{fds247327, Author = {Müller, B and Schäfer, A}, Title = {Decoherence time in high energy heavy ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {73}, Number = {5}, Pages = {054905}, Year = {2006}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/hep-ph/0512100.pdf}, Abstract = {We calculate the decoherence time of the ground state wave function of a nucleus in a high energy heavy ion collision. We define this time as the decay time of the ratio TrD2/TrD)2 of traces of the density matrix D. We find that this time is smaller or equal to 1/Qs, where the saturation scale Qs is defined within the color glass condensate model of parton saturation. Our result supports the notion that the extremely rapid entropy production deduced for the early stage of heavy ion collisions at collider energies is to a large extent caused by the decoherence of the initial-state wave functions. © 2006 The American Physical Society.}, Doi = {10.1103/PhysRevC.73.054905}, Key = {fds247327} } @article{fds247328, Author = {Ruppert, J and Renk, T and uuml, M and ller, B}, Title = {Mass and width of the rho meson in a nuclear medium from Brown-Rho scaling}, Journal = {Phys. Rev. C}, Volume = {73}, Pages = {034907}, Year = {2006}, url = {http://arxiv.org/pdf/hep-ph/0509134.pdf}, Abstract = {http://arxiv.org/abs/hep-ph/0509134}, Key = {fds247328} } @article{fds304595, Author = {Matinyan, SG and Müller, B}, Title = {Adventures of the coupled Yang-Mills oscillators: II. YM-Higgs quantum mechanics}, Journal = {Journal of Physics A: Mathematical and General}, Volume = {39}, Number = {1}, Pages = {61-72}, Year = {2006}, url = {http://dx.doi.org/10.1088/0305-4470/39/1/005}, Abstract = {We continue our study of the quantum mechanical motion in the x 2y2 potentials for n ≤ 2, 3, which arise in the spatially homogeneous limit of the Yang-Mills (YM) equations. In the present paper, we develop a new approach to the calculation of the partition function Z(t) beyond the Thomas-Fermi (TF) approximation by adding a harmonic (Higgs) potential and taking the limit v → 0, where v is the vacuum expectation value of the Higgs field. Using the Wigner-Kirkwood method to calculate higher-order corrections in ℏ, we show that the limit v → 0 leads to power-like singularities of the type v-n, which reflect the possibility of escape of the particle along the channels in the classical limit. We show how these singularities can be eliminated by taking into account the quantum fluctuations dictated by the form of the potential. © 2006 IOP Publishing Ltd.}, Doi = {10.1088/0305-4470/39/1/005}, Key = {fds304595} } @article{fds304596, Author = {Matinyan, SG and Müller, B}, Title = {Adventures of the coupled Yang-Mills oscillators: I. Semiclassical expansion}, Journal = {Journal of Physics A: Mathematical and General}, Volume = {39}, Number = {1}, Pages = {45-59}, Year = {2006}, url = {http://dx.doi.org/10.1088/0305-4470/39/1/004}, Abstract = {We study the quantum mechanical motion in the x2y2 potentials with n ≤ 2, 3, which arise in the spatially homogeneous limit of the Yang-Mills (YM) equations. These systems show strong stochasticity in the classical limit (ℏ ≤ 0) and exhibit a quantum mechanical confinement feature. We calculate the partition function Z(t) going beyond the Thomas-Fermi (TF) approximation by means of the semiclassical expansion using the Wigner-Kirkwood (WK) method. We derive a novel compact form of the differential equation for the WK function. After separating the motion in the channels of the equipotential surface from the motion in the central region, we show that the leading higher order corrections to the TF term vanish up to eighth order in ℏ, if we treat the quantum motion in the hyperbolic channels correctly by adiabatic separation of the degrees of freedom. Finally, we obtain an asymptotic expansion of the partition function in terms of the parameter g 2ℏ4t3. © 2006 IOP Publishing Ltd.}, Doi = {10.1088/0305-4470/39/1/004}, Key = {fds304596} } @article{Muller:2004dd, Author = {Müller, B.}, Title = {Heavy ions: Prospects at the LHC}, Journal = {Czech. J. Phys.}, Volume = {55}, Series = {Suppl. B}, Year = {2005}, url = {http://arxiv.org/pdf/hep-ph/0410115}, Abstract = {http://arxiv.org/abs/hep-ph/0410115}, Key = {Muller:2004dd} } @article{fds247192, Author = {Müller, B and Tan, C-I}, Title = {International Journal of Modern Physics A: Preface}, Journal = {International Journal of Modern Physics A}, Volume = {20}, Number = {19}, Pages = {vii}, Year = {2005}, Key = {fds247192} } @article{fds247253, Author = {Nonaka, C and Fries, RJ and Müller, B and Bass, SA and Asakawa, M}, Title = {Recombination plus fragmentation model at RHIC: Elliptic flow}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {31}, Number = {4}, Pages = {S429-S435}, Year = {2005}, url = {http://dx.doi.org/10.1088/0954-3899/31/4/053}, Abstract = {We discuss hadron production in relativistic heavy-ion collisions in the framework of the recombination and fragmentation model. We propose elliptic flow as a useful tool for exploring final interactions of resonances, the hadron structure of exotic particles and the phase structure of the reaction. © 2005 IOP Publishing Ltd.}, Doi = {10.1088/0954-3899/31/4/053}, Key = {fds247253} } @article{fds247254, Author = {Nonaka, C and Fries, RJ and Müller, B and Bass, SA and Asakawa, M}, Title = {Hadronization at RHIC: Interplay of recombination and fragmentation}, Journal = {Acta Physica Hungarica, Series A: Heavy Ion Physics}, Volume = {24}, Number = {1-4}, Pages = {227-233}, Year = {2005}, ISSN = {1219-7580}, url = {http://dx.doi.org/10.1556/APH.24.2005.1-4.31}, Abstract = {We discuss the hadron production in heavy ion collisions by the recombination and fragmentation model. We propose the elliptic flow as the useful tool for exploring final interactions for resonances, hadron structure for exotic particles and phase structure. © 2005 Akadémiai Kiadó, Budapest.}, Doi = {10.1556/APH.24.2005.1-4.31}, Key = {fds247254} } @article{fds247255, Author = {Nonaka, C and Müller, B and Bass, SA and Asakawa, M}, Title = {Possible resolutions of the D-puzzle}, Journal = {Physical Review C - Nuclear Physics}, Volume = {71}, Number = {5}, Year = {2005}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.71.051901}, Abstract = {We explore possible ways of explaining the net charge event-by-event fluctuations in Au+Au collisions observed in experiments at the Relativistic Heavy Ion Collider within a quark recombination model. We estimate the number of quarks at recombination and their implications for the predicted net charge fluctuations. We also discuss the consequences of diquark and quark-antiquark clustering above the deconfinement temperature. © 2005 The American Physical Society.}, Doi = {10.1103/PhysRevC.71.051901}, Key = {fds247255} } @article{fds247322, Author = {Matinyan, SG and M, B and uuml, and ller}, Title = {Adventures of the coupled Yang-Mills oscillators: II. YM-Higgs quantum mechanics}, Journal = {J. Phys. A}, Volume = {39}, Number = {1}, Pages = {45-59}, Year = {2005}, url = {http://arxiv.org/pdf/quant-ph/0506239}, Abstract = {http://arxiv.org/abs/quant-ph/0506239}, Doi = {10.1088/0305-4470/39/1/005}, Key = {fds247322} } @article{fds247323, Author = {Matinyan, SG and M, B and uuml, and ller}, Title = {Adventures of the coupled Yang-Mills oscillators: I. semiclassical expansion}, Journal = {J. Phys. A}, Volume = {39}, Number = {1}, Pages = {61-72}, Year = {2005}, url = {http://arxiv.org/pdf/quant-ph/0506214}, Abstract = {http://arxiv.org/abs/quant-ph/0506214}, Doi = {10.1088/0305-4470/39/1/004}, Key = {fds247323} } @article{fds247329, Author = {Fries, RJ and Müller, B and Srivastava, DK}, Title = {Centrality dependence of direct photons in Au + Au collisions at sNN=200 GeV}, Journal = {Physical Review C - Nuclear Physics}, Volume = {72}, Number = {4}, Pages = {041902(R)}, Year = {2005}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/nucl-th/0507018.pdf}, Abstract = {We calculate the spectra of high-energy photons emitted in relativistic Au + Au collisions for various centralities and compare to data recently collected at the Relativistic Heavy Ion Collider by the PHENIX Collaboration. Our results for photons from primary hard scatterings and photons from interactions of jets with the medium are consistent with the measurements of neutral pion and direct photon production in p+p collisions and give a good description of direct photon spectra measured in Au + Au collisions. The contribution of photons from jet-to-photon conversion in the medium can be as large as the photon yield from hard scatterings in the momentum range pT≈2-6 GeV/c. We show that this novel mechanism is not ruled out by any existing data. © 2005 The American Physical Society.}, Doi = {10.1103/PhysRevC.72.041902}, Key = {fds247329} } @article{fds247330, Author = {Müller, B and Rajagopal, K}, Title = {From entropy and jet quenching to deconfinement?}, Journal = {European Physical Journal C}, Volume = {43}, Number = {1-4}, Pages = {15-21}, Year = {2005}, url = {http://arxiv.org/pdf/hep-ph/0502174.pdf}, Abstract = {The challenge of demonstrating that the matter produced in heavy ion collisions is a deconfined quark-gluon plasma as predicted by lattice QCD calculations is the challenge of measuring the number of thermodynamic degrees of freedom $\nu\sim\varepsilon/T∧4$ at the time t 0 at which the matter comes into approximate local thermal equilibrium and begins to behave like a hydrodynamic fluid. Data from experiments done at the Relativistic Heavy Ion Collider have been used to estimate t 0 and to put a lower bound on the energy density $\varepsilon(t_0)$ . However measuring $\nu$ has seemed out of reach because no current data serve even as qualitative proxies for the temperature T(t 0). We point out that $\nu$ may equally appropriately be defined via $\nu\sim s∧4/\varepsilon∧3$ where s is the entropy density which can be estimated from the measured final state entropy. This estimate is based on the testable assumption of an isentropic expansion. The observation of jet quenching has the potential to provide an upper bound on the energy density at early times. Our goal is to motivate such an analysis by pointing out that it would set a lower bound on $\nu$. © Springer-Verlag 2005.}, Doi = {10.1140/epjc/s2005-02256-3}, Key = {fds247330} } @article{fds247331, Author = {Müller, B and Fries, RJ and Bass, SA}, Title = {Thermal recombination: Beyond the valence quark approximation}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {618}, Number = {1-4}, Pages = {77-83}, Year = {2005}, url = {http://arxiv.org/pdf/nucl-th/0503003.pdf}, Abstract = {Quark counting rules derived from recombination models agree well with data on hadron production at intermediate transverse momenta in relativistic heavy-ion collisions. They convey a simple picture of hadrons consisting only of valence quarks. We discuss the inclusion of higher Fock states that add sea quarks and gluons to the hadron structure. We show that, when recombination occurs from a thermal medium, hadron spectra remain unaffected by the inclusion of higher Fock states. However, the quark number scaling for elliptic flow is somewhat affected. We discuss the implications for our understanding of data from the Relativistic Heavy Ion Collider. © 2005 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.physletb.2005.05.025}, Key = {fds247331} } @article{fds247333, Author = {Nonaka, C and uuml, M and ller, B and Bass, SA and Asakawa, M}, Title = {Possible resolution of the D-paradox}, Journal = {Phys. Rev. C}, Volume = {71}, Pages = {051901}, Year = {2005}, Key = {fds247333} } @article{fds247334, Author = {Ruppert, J and Müller, B}, Title = {Waking the colored plasma}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {618}, Number = {1-4}, Pages = {123-130}, Year = {2005}, url = {http://arxiv.org/pdf/hep-ph/0503158.pdf}, Abstract = {We calculate the wake induced in a hot, dense QCD medium by a fast parton in the framework of linear response theory. We discuss two different scenarios: a weakly coupled quark-gluon plasma (pQGP) described by hard-thermal loop (HTL) perturbation theory and a strongly coupled QGP (sQGP), which had the properties of a quantum liquid. © 2005 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.physletb.2005.04.075}, Key = {fds247334} } @article{Muller:2004kk, Author = {Müller, B}, Title = {Hadronic signals of deconfinement at RHIC}, Journal = {Nuclear Physics A}, Volume = {750}, Number = {1 SPEC. ISS.}, Pages = {84-97}, Year = {2005}, url = {http://arxiv.org/pdf/nucl-th/0404015}, Abstract = {This article reviews (soft) hadronic signals of deconfinement and chiral symmetry restoration in hot QCD matter in the light of the results from the first three years of the experimental program at the relativistic heavy ion collider. © 2004 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.nuclphysa.2004.12.067}, Key = {Muller:2004kk} } @article{Fries:2004hd, Author = {Fries, RJ and Bass, SA and Müller, B}, Title = {Correlated emission of hadrons from recombination of correlated partons}, Journal = {Physical Review Letters}, Volume = {94}, Number = {12}, Pages = {122301}, Year = {2005}, ISSN = {0031-9007}, url = {http://arxiv.org/pdf/nucl-th/0407102}, Abstract = {We discuss different sources of hadron correlations in relativistic heavy ion collisions. We show that correlations among partons in a quasithermal medium can lead to the correlated emission of hadrons by quark recombination and argue that this mechanism offers a plausible explanation for the dihadron correlations in the few GeV/c momentum range observed in Au + Au collisions at the BNL Relativistic Heavy Ion Collider. © 2005 The American Physical Society.}, Doi = {10.1103/PhysRevLett.94.122301}, Key = {Fries:2004hd} } @article{Bass:2004de, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Photon interferometry of Au+Au collisions at the BNL Relativistic Heavy-Ion Collider.}, Journal = {Physical Review Letters}, Volume = {93}, Number = {16}, Pages = {162301}, Year = {2004}, Month = {October}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15524982}, Abstract = {We calculate the two-body correlation function of direct photons produced in central Au+Au collisions at the Relativistic Heavy-Ion Collider. Our calculation includes contributions from the early preequilibrium phase in which photons are produced via hard parton scatterings as well as radiation of photons from a thermalized quark-gluon plasma and the subsequent expanding hadron gas. We find that high energy photon interferometry provides a faithful probe of the details of the space-time evolution and of the early reaction stages of the system.}, Doi = {10.1103/PhysRevLett.93.162301}, Key = {Bass:2004de} } @article{Fries:2003fr, Author = {Fries, RJ and Mueller, B}, Title = {Heavy ions at LHC: Theoretical issues}, Journal = {The European Physical Journal C - Particles and Fields}, Volume = {34}, Pages = {S279-S285}, Year = {2004}, Month = {July}, ISSN = {1434-6044}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000207563100027&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {http://arxiv.org/abs/nucl-th/0307043}, Doi = {10.1140/epjcd/s2004-04-026-6}, Key = {Fries:2003fr} } @article{fds247231, Author = {Müller, B}, Title = {Musings about the Few-Body Problem}, Journal = {Nuclear Physics A}, Volume = {737}, Number = {SUPPL.}, Pages = {3-6}, Year = {2004}, url = {http://dx.doi.org/10.1016/j.nuclphysa.2004.03.216}, Abstract = {I review some anecdotal history of the few-body problem in physics, survey the present scope of the field, and mention some unsolved problems as possible future challenges. © 2004 Published by Elsevier B.V.}, Doi = {10.1016/j.nuclphysa.2004.03.216}, Key = {fds247231} } @article{fds247248, Author = {Bass, SA and Müller, B and Stephans, GSF and Ullrich, T}, Title = {Preface: The 7th International Conference on Strangeness in Quark Matter}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {30}, Number = {1}, Pages = {i-ii}, Year = {2004}, Key = {fds247248} } @article{fds247250, Author = {Fries, RJ and Müller, B and Nonaka, C and Bass, SA}, Title = {Hadronization in heavy-ion collisions: Recombination or fragmentation?}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {30}, Number = {1}, Pages = {S223-S228}, Year = {2004}, url = {http://dx.doi.org/10.1088/0954-3899/30/1/025}, Abstract = {We show that hadron production in relativistic heavy-ion collisions at transverse momenta larger than 2 GeV/c can be explained by the competition of two different hadronization mechanisms. Above 5 GeV/c hadron production can be described by fragmentation of partons that are created perturbatively. Below 5 GeV/c recombination of partons from the dense and hot fireball dominates. This can explain some of the surprising features of RHIC data such as the constant baryon-to-meson ratio of about one and the small nuclear suppression for baryons between 2 to 4 GeV/c.}, Doi = {10.1088/0954-3899/30/1/025}, Key = {fds247250} } @article{Müller:2004ce, Author = {uuml, M and ller, B and Srivastava, DK}, Title = {How relativistic heavy ion collisions can help us}, Journal = {Physics News (Indian Physics Association)}, Volume = {35}, Number = {2-4}, Pages = {3-10}, Year = {2004}, url = {http://arxiv.org/pdf/nucl-th/0407010}, Abstract = {http://arxiv.org/abs/nucl-th/0407010}, Key = {Müller:2004ce} } @article{Nonaka:2003ew, Author = {Nonaka, C and uuml, M and ller, B and Asakawa, M and Bass, SA}, Title = {Elliptic flow of resonances at RHIC: Probing final state}, Journal = {Phys. Rev. C}, Volume = {69}, Number = {3}, Pages = {031902}, Year = {2004}, url = {http://arxiv.org/pdf/nucl-th/0312081}, Abstract = {http://arxiv.org/abs/nucl-th/0312081}, Doi = {10.1103/PhysRevC.69.031902}, Key = {Nonaka:2003ew} } @article{Biro:2004na, Author = {Biró, TS and Purcsel, G and Müller, B}, Title = {What is the temperature in heavy ion collisions?}, Journal = {Acta Physica Hungarica, Series A: Heavy Ion Physics}, Volume = {21}, Number = {1}, Pages = {85-94}, Year = {2004}, url = {http://arxiv.org/pdf/hep-ph/0404115}, Abstract = {We consider the Tsallis distribution as a source of the apparent slope of one-particle spectra in heavy-ion collisions and investigate the equation of state of this special kind of quark matter in the framework of non-extensive thermodynamics. We relate the energy per particle to the power-law tail of spectra at a given temperature.}, Doi = {10.1556/APH.21.2004.1.9}, Key = {Biro:2004na} } @article{Bass:2004vh, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {RHIC physics with the parton cascade model}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {30}, Number = {8}, Pages = {S1283-S1286}, Year = {2004}, ISSN = {1219-7580}, url = {http://arxiv.org/pdf/nucl-th/0403033}, Abstract = {We present an analysis of the net baryon number rapidity distribution and of direct photon emission in the framework of the parton cascade model.}, Doi = {10.1088/0954-3899/30/8/109}, Key = {Bass:2004vh} } @article{Biro:2003vz, Author = {Biró, TS and Müller, B}, Title = {Almost exponential transverse spectra from power law spectra}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {578}, Number = {1-2}, Pages = {78-84}, Year = {2004}, url = {http://arxiv.org/pdf/hep-ph/0309052}, Abstract = {We point out that exponential shape of transverse spectra can be obtained as the Fourier transform of the limiting distribution of randomly positioned partons with power law spectra given by pQCD, which actually realize Tsallis distributions. Such spectra were used to obtain hadron yields by recombination in relativistic heavy-ion collisions at RHIC energies. © 2003 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.physletb.2003.10.052}, Key = {Biro:2003vz} } @article{fds304598, Author = {Nonaka, C and Müller, B and Asakawa, M and Bass, SA and Fries, RJ}, Title = {Elliptic flow of resonances in relativistic heavy ion collisions: Probing final state interactions and the structure of resonances}, Journal = {Physical Review C - Nuclear Physics}, Volume = {69}, Number = {3}, Pages = {031902-031901}, Year = {2004}, url = {http://dx.doi.org/10.1103/PhysRevC.69.031902}, Abstract = {We propose the measurement of the elliptic flow of hadron resonances at the Relativistic Heavy Ion Collider as a tool to probe the amount of hadronic final state interactions for resonances at intermediate and large transverse momenta. This can be achieved by looking at systematic deviations of the measured flow coefficient ν2 from the scaling law given by the quark recombination formalism. Our method can be generalized to explore the structure of exotic particles, such as the recently found pentaquark Θ+(1540).}, Doi = {10.1103/PhysRevC.69.031902}, Key = {fds304598} } @article{Fries:2003vb, Author = {Fries, RJ and Müller, B and Nonaka, C and Bass, SA}, Title = {Hadronization in heavy-ion collisions: recombination and fragmentation of partons.}, Journal = {Physical Review Letters}, Volume = {90}, Number = {20}, Pages = {202303}, Year = {2003}, Month = {May}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12785886}, Abstract = {We argue that the emission of hadrons with transverse momentum up to about 5 GeV/c in central relativistic heavy ion collisions is dominated by recombination, rather than fragmentation of partons. This mechanism provides a natural explanation for the observed constant baryon-to-meson ratio of about one and the apparent lack of a nuclear suppression of the baryon yield in this momentum range. Fragmentation becomes dominant at higher transverse momentum, but the transition point is delayed by the energy loss of fast partons in dense matter.}, Doi = {10.1103/PhysRevLett.90.202303}, Key = {Fries:2003vb} } @article{Bass:2002pm, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Light from cascading partons in relativistic heavy-ion collisions.}, Journal = {Physical Review Letters}, Volume = {90}, Number = {8}, Pages = {082301}, Year = {2003}, Month = {February}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12633418}, Abstract = {We calculate the production of high energy photons from Compton and annihilation processes as well as fragmentation off quarks in the parton cascade model. The multiple scattering of partons is seen to lead to a substantial production of high energy photons, which rises further when parton multiplication due to final state radiation is included. The photon yield is found to be directly proportional to the number of hard collisions and thus provides valuable information on the preequilibrium reaction dynamics.}, Doi = {10.1103/PhysRevLett.90.082301}, Key = {Bass:2002pm} } @article{Muller:2003dn, Author = {Müller, B.}, Title = {Parton cascades in high-energy nuclear collisions}, Journal = {Int. J. Mod. Phys. E}, Volume = {12}, Pages = {165-176}, Year = {2003}, Key = {Muller:2003dn} } @article{fds28625, Author = {T.S. Biro and B. Müller and S.G. Matinyan}, Title = {Beyond quantum field theory: Chaotic lattices?}, Year = {2003}, url = {http://arxiv.org/pdf/hep-lat/0305023.pdf}, Abstract = {http://arxiv.org/abs/hep-lat/0305023}, Key = {fds28625} } @article{fds4367, Author = {Bass, S. A. and Müller, B. and Srivastava, D. K.}, Title = {Semihard scattering of partons at SPS and RHIC: A study in contrast}, Journal = {Phys. Rev. C}, Volume = {66}, Pages = {061902(R)}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0210042.pdf}, Abstract = {http://arxiv.org/abs/nucl-th/0210042}, Key = {fds4367} } @article{fds28626, Author = {T.S. Biro and S.G. Matinyan and B. Müller}, Title = {Chaotic quantization: Maybe the Lord plays dice, after all?}, Volume = {633}, Series = {Lecture Notes in Physics}, Pages = {164-179}, Booktitle = {Decoherence and Entropy in Complex Systems}, Publisher = {Springer-Verlag}, Editor = {H.T. Elze}, Year = {2003}, url = {http://arxiv.org/pdf/hep-th/0301131.pdf}, Abstract = {http://erxiv.org/abs/hep-th/0301131}, Key = {fds28626} } @article{fds247246, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Parton rescattering and colour screening in Au+Au collisions at RHIC}, Journal = {Nuclear Physics A}, Volume = {715}, Pages = {813c-816c}, Year = {2003}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/S0375-9474(02)01501-4}, Abstract = {We study the microscopic dynamics of quarks and gluons in relativistic heavy ion collisions in the framework of the Parton Cascade Model. We use lowest order perturbative QCD cross sections with fixed lower momentum cutoff p Tmin. We calculate the time evolution of the Debye-screening mass μD for Au+Au collisions at √s = 200 GeV per nucleon pair. We also determine the energy density reached through hard and semi-hard processes at RHIC and analyze the extent of perturbative rescattering among partons. © 2003 Elsevier Science E.V. All rights reserved.}, Doi = {10.1016/S0375-9474(02)01501-4}, Key = {fds247246} } @article{Bass:2002fh, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Parton rescattering and screening in Au + Au collisions at RHIC}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {551}, Number = {3-4}, Pages = {277-283}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0207042}, Abstract = {We study the microscopic dynamics of quarks and gluons in relativistic heavy ion collisions in the framework of the Parton Cascade Model. We use lowest order perturbative QCD cross sections with fixed lower momentum cutoff PTmin. We calculate the time-evolution of the Debye-screening mass μD for Au + Au collisions at √s = 200 GeV per nucleon pair. The screening mass is used to determine a lower limit for the allowed range of PTmin. We also determine the energy density reached through hard and semi-hard processes at RHIC, obtain a lower bound for the rapidity density of charged hadrons produced by semi-hard interactions, and analyze the extent of perturbative rescattering among partons. © 2002 Elsevier Science B.V. All rights reserved.}, Doi = {10.1016/S0370-2693(02)03068-X}, Key = {Bass:2002fh} } @article{Fries:2002kt, Author = {Fries, RJ and Müller, B and Srivastava, DK}, Title = {High-energy photons from passage of jets through quark-gluon plasma}, Journal = {Physical Review Letters}, Volume = {90}, Number = {13}, Pages = {132301/1-132301/4}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0208001}, Abstract = {A novel mechanism for the production of high-energy photons in relativistic heavy ion collisions is presented. Calculations indicate that this mechanism is the leading source of directly produced photons at RHIC in the region p⊥≤6 GeV/c.}, Doi = {10.1103/PhysRevLett.90.132301}, Key = {Fries:2002kt} } @article{Bass:2002vm, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Net baryon density in Au + Au collisions at the relativistic heavy ion collider}, Journal = {Physical Review Letters}, Volume = {91}, Number = {5}, Pages = {523021-523024}, Year = {2003}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12906590}, Abstract = {The net-baryon multiplicity density distributions in Au + Au collisions were calculated at 130 and 200 GeV center-of-mass energy per nucleon pair. The parton cascade model predicted a net-baryon excess at midrapidity in Au + Au collisions, which was in agreement with measured values. The transport of partons to midrapidity, caused by rescattering among partons, was found to increase the net-baryon number density.}, Doi = {10.1103/PhysRevLett.91.052302}, Key = {Bass:2002vm} } @article{Bass:2003mk, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Transverse momentum distribution of net baryon number at RHIC}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {29}, Number = {10}, Pages = {L51-L58}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0307027}, Abstract = {We calculate the transverse momentum distribution of net quarks (quarks minus antiquarks) in Au+Au collisions at the Relativistic Heavy Ion Collider in the framework of the parton cascade model at two different rapidities. Parton re-scattering and fragmentation are seen to lead to a substantial difference in the slopes of these distributions between mid- and forward-rapidities, in qualitative agreement with the corresponding data for the net baryon distribution.}, Doi = {10.1088/0954-3899/29/10/101}, Key = {Bass:2003mk} } @article{Asakawa:2002vj, Author = {Asakawa, M and Minakata, H and Müller, B}, Title = {Negative elliptic flow from anomaly induced DCC formation}, Journal = {Nuclear Physics A}, Volume = {721}, Pages = {305c-308c}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0212070}, Abstract = {We discuss characteristic experimental signatures related to the mechanism of DCC formation triggered by the chiral U(l) anomaly in relativistic heavy ion collisions. We predict an enhancement of the fraction of neutral pions compared with all pions in the direction perpendicular to the scattering plane. To quantify the effect on the angular distribution of neutral pions, we compute the elliptic flow parameter u2 as a function of the transverse momentum. We find values of order -0.05 at small momenta for neutral pions. We also compute the v2 parameter for inclusive photons, which is easier to measure, and confirmed that the negative a few percent effect prevails in this observable.}, Doi = {10.1016/S0375-9474(03)01056-X}, Key = {Asakawa:2002vj} } @article{Fries:2003kq, Author = {Fries, RJ and Müller, B and Nonaka, C and Bass, SA}, Title = {Hadron production in heavy ion collisions: Fragmentation and recombination from a dense parton phase}, Journal = {Physical Review C - Nuclear Physics}, Volume = {68}, Number = {4}, Pages = {449021-4490223}, Year = {2003}, ISSN = {0556-2813}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000187575300046&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {We discuss hadron production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC). We argue that hadrons at transverse momenta P T<5 GeV are formed by recombination of partons from the dense parton phase created in central collisions at RHIC. We provide a theoretical description of the recombination process for PT>2 GeV. Below PT=2 GeV our results smoothly match a purely statistical description. At high transverse momentum hadron production is well described in the language of perturbative QCD by the fragmentation of partons. We give numerical results for a variety of hadron spectra, ratios, and nuclear suppression factors. We also discuss the anisotropic flow v2 and give results based on a flow in the parton phase. Our results are consistent with the existence of a parton phase at RHIC hadronizing at a temperature of 175 MeV and a radial flow velocity of 0.55c.}, Doi = {10.1103/PhysRevC.68.044902}, Key = {Fries:2003kq} } @article{Muller:2002fa, Author = {uuml, M and ller, B}, Title = {Phenomenology of jet quenching in heavy ion collisions}, Journal = {Phys. Rev. C}, Volume = {67}, Number = {6}, Pages = {061901}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0208038}, Abstract = {http://arxiv.org/abs/nucl-th/0208038}, Doi = {10.1103/PhysRevC.67.061901}, Key = {Muller:2002fa} } @article{Shin:2003yk, Author = {Shin, GR and Müller, B}, Title = {Studies of parton thermalization at RHIC}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {29}, Number = {11}, Pages = {2485-2495}, Year = {2003}, url = {http://arxiv.org/pdf/nucl-th/0307084}, Abstract = {We consider the evolution of a parton system which is formed in the central region just after a relativistic heavy ion collision. The parton consists of mostly gluons, minijets, which are produced by elastic scattering between constituent partons of the colliding nuclei. We assume that the system can be described by a semi-classical Boltzmann transport equation, which we solve by means of the test particle Monte Carlo method including retardation. The partons proliferate via secondary radiative gg → ggg processes until the thermalization is reached for some assumptions. The extended system is thermalized at about t = 1.6 fm c-1 with T = 570 MeV and remains in kinetic equilibrium for about 2 fm c-1 with breaking temperature T = 360 MeV in the rapidity central region.}, Doi = {10.1088/0954-3899/29/11/004}, Key = {Shin:2003yk} } @article{fds247607, Author = {Müller, B}, Title = {Parton cascades in high energy nuclear collisions}, Journal = {International Journal of Modern Physics E}, Volume = {12}, Number = {2}, Pages = {165-176}, Year = {2003}, url = {http://dx.doi.org/10.1142/S0218301303001247}, Abstract = {This is a review of the parton cascade model (PCM) which provides a QCD-based description of nucleus-nucleus reactions at very high energy. The PCM describes the collision dynamics within the early and dense phase of the reaction in terms of the relativistic, probabilistic transport of perturbative excitations (partons) of the QCD vacuum, combined with the renormalization group flow of the parton virtuality. The current state of numerical implementations of the model, as well as its predictions for nuclear collisions at RHIC and LHC are discussed.}, Doi = {10.1142/S0218301303001247}, Key = {fds247607} } @article{fds304594, Author = {Müller, B}, Title = {Phenomenology of jet quenching in heavy ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {67}, Number = {6}, Pages = {619011-619015}, Year = {2003}, Abstract = {We derive an analytical expression for the quenching factor in the strong quenching limit where the pT spectrum of hard partons is dominated by surface emission. We explore the phenomenological consequences of different scaling laws for the energy loss and calculate the additional suppression of the away-side jet.}, Key = {fds304594} } @article{Bass:2002gb, Author = {S A Bass and BM and uuml, and ller, DKS}, Title = {Semihard scattering of partons at SPS and RHIC: A Study in contrast.}, Journal = {Phys. Rev. C, Rapid Communication}, Volume = {66}, Pages = {061902(R)}, Year = {2002}, Month = {December}, url = {http://arxiv.org/abs/nucl-th/0210042}, Abstract = {We analyze the contribution of pQCD based semi-hard parton (re)scattering to the reaction dynamics of relativistic heavy-ion collisions at SPS and RHIC. While such processes are able to account for the measured yield of high momentum direct photons at SPS energies, the conditions necessary for jet-quenching are not fulfilled. The situation changes dramatically at RHIC energies.}, Key = {Bass:2002gb} } @article{fds3051, Author = {Müller, B.}, Title = {The anthropic principle revisited}, Booktitle = {From integrable models to gauge theories}, Publisher = {World Scientific (Singapore)}, Editor = {Gürzadyan, V.G. et al.}, Year = {2002}, url = {http://arxiv.org/pdf/astro-ph/0108259.pdf}, Abstract = {The usage of the anthropic principle in modern cosmology is reviewed. It is argued that its recent use to explain the observedvalues of cosmological parameters as most probable values for an ensemble of universes, is not justified. However, the anthropic principle can be invoked to argue that a vast number of universes must exist, in which the cosmological parameters and constants of nature take on different values. This argument lends support to the hypothesis of eternal inflation and suggests that at least some of the parameters of the Standard Model cannot be quantitatively derived from an underlying theory.}, Key = {fds3051} } @article{Asakawa:2000dr, Author = {Asakawa, M and Minakata, H and uuml, M and ller, B}, Title = {Experimental signatures of anomaly induced DCC formation}, Journal = {Phys. Rev. C}, Volume = {65}, Number = {5}, Pages = {057901}, Year = {2002}, url = {http://arxiv.org/pdf/nucl-th/0011031}, Abstract = {http://arxiv.org/abs/nucl-th/0011031}, Key = {Asakawa:2000dr} } @article{Asakawa:2001mn, Author = {Asakawa, M and Heinz, U and Müller, B}, Title = {Fluctuation probes of quark deconfinement}, Journal = {Nuclear Physics A}, Volume = {698}, Number = {1-4}, Pages = {519c-522c}, Year = {2002}, ISSN = {0375-9474}, url = {http://arxiv.org/pdf/nucl-th/0106046}, Abstract = {http://arxiv.org/abs/nucl-th/0106046}, Key = {Asakawa:2001mn} } @article{Muller:2001wj, Author = {Müller, B}, Title = {Statistical fluctuations as probes of dense matter}, Journal = {Nuclear Physics A}, Volume = {702}, Number = {1-4}, Pages = {281c-290c}, Year = {2002}, ISSN = {0375-9474}, url = {http://arxiv.org/pdf/nucl-th/0111008}, Abstract = {The use of statistical fluctuations as probes of the microscopic dynamics of hot and dense hadronic matter is reviewed. Critical fluctuations near the critical point of QCD matter are predicted to enhance fluctuations in pionic observables. Chemical fluctuations, especially those of locally conserved quantum numbers, such as electric charge and baryon number, can probe the nature of the carriers of these quantum numbers in the dense medium.}, Key = {Muller:2001wj} } @article{Shin:2002fg, Author = {Shin, GR and Müller, B}, Title = {A relativistic parton cascade with radiation}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {28}, Number = {10}, Pages = {2643-2655}, Year = {2002}, url = {http://arxiv.org/pdf/nucl-th/0207041}, Abstract = {We consider the evolution of a parton system which is formed at the central rapidity region just after an ultrarelativistic heavy-ion collision. The evolution of the system, which is composed of gluons, quarks and antiquarks, is described by relativistic Boltzmann equations with collision terms including radiation and retardation effects. The equations are solved by the test particle method using Monte Carlo sampling. Our simulations do not show any evidence of kinetic equilibration, unless the cross sections are artificially increased to unrealistically large values.}, Doi = {10.1088/0954-3899/28/10/309}, Key = {Shin:2002fg} } @article{fds287695, Author = {Bass, SA and Müller, B and Srivastava, DK}, Title = {Semihard scattering of partons at √s=17 vs 200 GeV: A study in contrast}, Journal = {Physical Review C - Nuclear Physics}, Volume = {66}, Number = {6}, Pages = {619021-619024}, Year = {2002}, Abstract = {We analyze the contribution of perturbative QCD based semihard parton (re)scattering to the reaction dynamics of relativistic heavy-ion collisions at SPS and RHIC. While such processes are able to account for the measured yield of high-momentum direct photons at SPS energies, the conditions necessary for jet quenching are not fulfilled. The situation changes dramatically at RHIC energies.}, Key = {fds287695} } @article{fds304593, Author = {Asakawa, M and Minakata, H and Müller, B}, Title = {Experimental signatures of anomaly induced disoriented chiral condensate formation}, Journal = {Physical Review C - Nuclear Physics}, Volume = {65}, Number = {5}, Pages = {579011-579013}, Year = {2002}, Abstract = {We discuss characteristic experimental signatures related to the formation of domains of disoriented chiral condensate triggered by the axial anomaly in relativistic heavy-ion collisions. We predict that the enhancement of the fraction of neutral pions compared to all pions depends on the angle of emission with respect to the scattering plane and is concentrated at small transverse momentum and small rapidity in the center-of-mass frame. The anisotropy with respect to the reaction plane is also observable in the inclusive photon distribution.}, Key = {fds304593} } @article{Biro:2001dh, Author = {Biró, TS and Matinyan, SG and Müller, B}, Title = {Chaotic quantization of classical gauge fields}, Journal = {Foundations of Physics Letters}, Volume = {14}, Number = {5}, Pages = {471-485}, Year = {2001}, url = {http://arxiv.org/pdf/hep-th/0105279}, Abstract = {We argue that the quantized non-Abelian gauge theory can be obtained as the infrared limit of the corresponding classical gauge theory in a higher dimension. We show how the transformation from classical to quantum field theory emerges, and calculate Planck's constant from quantities defined in the underlying classical gauge theory.}, Doi = {10.1023/A:1015565621215}, Key = {Biro:2001dh} } @article{fds324422, Author = {Pisarski, RD and Kapusta, JI and Mueller, B}, Title = {Klaus Kinder-Geiger - Obituary}, Journal = {Physics today}, Volume = {53}, Number = {4}, Pages = {88-88}, Year = {2000}, Month = {April}, url = {http://dx.doi.org/10.1063/1.883060}, Doi = {10.1063/1.883060}, Key = {fds324422} } @article{Fries:2000da, Author = {Fries, RJ and Schäfer, A and Stein, E and Müller, B}, Title = {Nuclear enhanced higher-twist effects in the Drell-Yan process}, Journal = {Nuclear Physics B}, Volume = {582}, Number = {1-3}, Pages = {537-570}, Year = {2000}, url = {http://arxiv.org/pdf/hep-ph/0002074}, Abstract = {We calculate the Drell-Yan cross section, resolving the full kinematics of the lepton pair, at high transverse momentum for hadron nucleus collisions. We use the general framework of Luo, Qiu and Sterman to calculate double scattering contributions that are of twist-4 and demonstrate their nuclear enhancement. By comparing single and double scattering at RHIC energies we find that double scattering gives contributions of comparable size. We also show that the angular dependence of the Drell-Yan pair discriminates between the various double scattering contributions. © 2000 Elsevier Science B.V.}, Key = {Fries:2000da} } @article{Bolte:1999th, Author = {Bolte, JM and uuml, and ller, B and Sch, and auml, and fer, A}, Title = {Ergodic properties of classical SU(2) lattice gauge theory}, Journal = {Phys. Rev. D}, Volume = {61}, Number = {5}, Pages = {054506}, Year = {2000}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-lat/9906037}, Abstract = {http://arxiv.org/abs/hep-lat/9906037}, Key = {Bolte:1999th} } @article{Asakawa:2000wh, Author = {Asakawa, M and Heinz, U and Müller, B}, Title = {Fluctuation probes of quark deconfinement}, Journal = {Physical Review Letters}, Volume = {85}, Number = {10}, Pages = {2072-2075}, Year = {2000}, url = {http://arxiv.org/pdf/hep-ph/0003169}, Abstract = {A different type of fluctuations in the multiplicities and momentum distributions of particles emitted in relativistic heavy-ion collisions is considered. These fluctuations are sensitive to the microscopic structure of the dense matter. The fluctuations of locally observed quantities that show a distinctly different behavior in a hadron gas (HG) and a quark-gluon plasma (QGP) was considered since the expansion is too fast for local fluctuations to follow the mean thermodynamic evolution of the system.}, Doi = {10.1103/PhysRevLett.85.2072}, Key = {Asakawa:2000wh} } @article{Poschl:2000ip, Author = {Pöschl, W and Müller, B}, Title = {Collision of SU(2) gauge fields in 3+1 dimensions}, Journal = {Computer Physics Communications}, Volume = {125}, Number = {1}, Pages = {282-315}, Year = {2000}, url = {http://www.elsevier.com/IVP/00104655/125/282}, Abstract = {The Yang-Mills equations provide a classical mean field description of the non-Abelian soft glue field dynamics in heavy ion collisions at high energies. A C++ code for the numerical solution on a three-dimensional gauge lattice is presented. Non-perturbative time-dependent solutions in position space are calculated in the weak coupling regime of a gauge lattice within the Hamiltonian approach of Kogut and Susskind. Applications are demonstrated by simulations of the Yang-Mills field dynamics in collisions of initially uniformly color polarized Gaussian wave packets. The collisions are evolved in time. The time dependent energy densities, energy flows and energy currents in longitudinal and transverse directions with respect to the collision axis are presented. Simulations of this type have recently revealed an interesting solution which exhibits a time-delayed sudden increase of the transverse energy currents in the `non-Abelian case' at short times after the collision.}, Doi = {10.1016/S0010-4655(99)00484-1}, Key = {Poschl:2000ip} } @article{fds304591, Author = {Bolte, J and Müller, B and Schäfer, A}, Title = {Ergodic properties of classical SU(2) lattice gauge theory}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {61}, Number = {5}, Pages = {DUMMY35}, Year = {2000}, ISSN = {0556-2821}, Abstract = {We investigate the relationship between the Lyapunov exponents of periodic trajectories, the average and fluctuations of Lyapunov exponents of ergodic trajectories, and the ergodic autocorrelation time for the twodimensional hyperbola billiard. We then study the fluctuation properties of the ergodic Lyapunov spectrum of classical SU(2) gauge theory on a lattice. Our results are consistent with the notion that this system is globally hyperbolic. Among the many powerful theorems applicable to such systems, we discuss one relating to the fluctuations in the entropy growth rate. ©2000 The American Physical Society.}, Key = {fds304591} } @article{fds304592, Author = {Bolte, J and Müller, B and Schäfer, A}, Title = {Ergodic properties of classical SU(2) lattice gauge theory}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {61}, Number = {5}, Pages = {1-7}, Year = {2000}, ISSN = {0556-2821}, Abstract = {We investigate the relationship between the Lyapunov exponents of periodic trajectories, the average and fluctuations of Lyapunov exponents of ergodic trajectories, and the ergodic autocorrelation time for the two-dimensional hyperbola billiard. We then study the fluctuation properties of the ergodic Lyapunov spectrum of classical SU(2) gauge theory on a lattice. Our results are consistent with the notion that this system is globally hyperbolic. Among the many powerful theorems applicable to such systems, we discuss one relating to the fluctuations in the entropy growth rate. ©2000 The American Physical Society.}, Key = {fds304592} } @article{fds247224, Author = {Rafelski, J and Müller, B}, Title = {Quarks unleashed at low energy}, Journal = {Physics World}, Volume = {12}, Number = {3}, Pages = {23-24}, Year = {1999}, ISSN = {0953-8585}, Key = {fds247224} } @article{fds247226, Author = {Müller, B}, Title = {Quark matter '99 - Theoretical summary: What next?}, Journal = {Nuclear Physics A}, Volume = {661}, Number = {1-4}, Pages = {272c-281c}, Year = {1999}, Key = {fds247226} } @article{Bass:1999bu, Author = {Bass, SA and Müller, B}, Title = {K-factors in parton cascades at RHIC and SPS}, Journal = {Physics Letters B}, Volume = {471}, Number = {2-3}, Pages = {108-112}, Year = {1999}, ISSN = {0370-2693}, url = {http://arxiv.org/pdf/nucl-th/9908014}, Abstract = {Different treatments for the inclusion of higher-order perturbative QCD corrections in parton based transport models of relativistic heavy-ion collisions are studied and their influence on experimental observables is investigated. At RHIC, particle multiplicities may vary by more than 30%, depending on the correction scheme. A detailed analysis of the squared relative momentum transfers Q2 to be expected in parton (re)scatterings at RHIC casts doubt on the applicability of pQCD based transport approaches at the SPS and rules out the application of higher-order correction schemes based on a rescaling of Q2 in the running coupling constant α(s), at all energies. (C) 1999 Published by Elsevier Science B.V.}, Doi = {10.1016/S0370-2693(99)01364-7}, Key = {Bass:1999bu} } @article{Poschl:1998px, Author = {ouml, P and schl, W and uuml, M and ller, B}, Title = {Real time dynamics of colliding gauge fields and the 'glue burst'}, Journal = {Phys. Rev. D}, Volume = {60}, Number = {11}, Pages = {114505}, Year = {1999}, url = {http://arxiv.org/pdf/nucl-th/9812066}, Abstract = {http://arxiv.org/abs/nucl-th/9812066}, Key = {Poschl:1998px} } @article{Bass:1998nz, Author = {Bass, SA and Müller, B and Pöschl, W}, Title = {Lattice gauge description of colliding nuclei}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {25}, Number = {11}, Pages = {L109-L115}, Year = {1999}, ISSN = {0954-3899}, url = {http://arxiv.org/pdf/nucl-th/9808011}, Abstract = {We propose a novel formalism for simultaneously describing both the hard and soft parton dynamics in ultrarelativistic collisions of nuclei. The emission of gluons from the initially coherent parton configurations of the colliding nuclei and low-p1 colour coherence effects are treated in the framework of a Yang-Mills transport equation on a coupled lattice-particle system. A collision term is added to the transport equation to account for the remaining intermediate and high-p1 interactions in an infrared finite manner.}, Doi = {10.1088/0954-3899/25/11/101}, Key = {Bass:1998nz} } @article{Fries:1999jj, Author = {Fries, RJ and Müller, B and Schäfer, A and Stein, E}, Title = {Angular Dependence of the Nuclear Enhancement of Drell-Yan Pairs}, Journal = {Physical Review Letters}, Volume = {83}, Number = {21}, Pages = {4261-4264}, Year = {1999}, url = {http://arxiv.org/pdf/hep-ph/9907567}, Abstract = {We calculate the nuclear enhancement in the angular distribution of Drell-Yan pairs produced in proton-nucleus reactions. Nuclear effects are encoded in universal twist-4 parton correlation functions. We find that the Lam-Tung relation for the angular coefficients of the lepton-pair distribution holds for the double-hard, but not for the soft-hard, contribution. We also predict that nuclear enhancement effects at the Relativistic Heavy Ion Collider energies can be large.}, Key = {Fries:1999jj} } @article{fds304590, Author = {Pöschl, W and Müller, B}, Title = {Real time dynamics of colliding gauge fields and the "glue burst"}, Journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, Volume = {60}, Number = {11}, Pages = {1-16}, Year = {1999}, Abstract = {The Yang-Mills equations provide a classical mean field description of gauge fields. In view of developing a coherent description of the formation of the quark gluon plasma in high energetic nucleus-nucleus collisions we study pure gauge field dynamics in 3 + 1 dimensions. In collisions of wave packets, numerically simulated on a SU(2) gauge lattice, we study transverse and longitudinal energy currents. For wave packets with different polarizations in color space, we observe a time-delayed fragmentation after the collision resulting in a rapid expansion into transverse directions. We call this phenomenon the "glue burst." An analysis of the Yang-Mills equations reveals the explanation for this behavior. It is pointed out that this effect could play a role in ultrarelativistic heavy-ion collisions. ©1999 The American Physical Society.}, Key = {fds304590} } @article{fds247221, Author = {Müller, B}, Title = {Signatures for the quark-gluon plasma}, Journal = {Nuclear Physics A}, Volume = {630}, Number = {1-2}, Pages = {461c-467c}, Year = {1998}, Abstract = {I survey the experimental signatures of a quark-gluon plasma in the light of present and future experiments. This includes a review of new theoretical results concerning the QCD equation of state and the formation of a dense parton plasma in high energy nuclear collisions.}, Key = {fds247221} } @article{fds247222, Author = {Asakawa, M and Minakata, H and Müller, B}, Title = {Non-central heavy-ion collisions are the place to look for DCC}, Journal = {Nuclear Physics A}, Volume = {638}, Number = {1-2}, Pages = {443c-446c}, Year = {1998}, Abstract = {We give two reasons why we believe that non-central ultrarelativistic heavy ion collisions are the place to look for the disoriented chiral condensates (DCC). First, we argue that the most probable quench scenario for the formation of DCC requires non-central collisions. Second, we show by numerical simulations that strong electromagnetic fields of heavy ions can exert a surprisingly large effect on the DCC domain formation through the chiral anomaly. The effect again requires non-central collisions. Interestingly, the result of simulations is consistent with the formation of correlated two domains of the chiral condensate, which are aligned in space, perpendicular to the scattering plane, but misaligned in isospin space.}, Key = {fds247222} } @article{Geiger:1998ct, Author = {Geiger, K and Müller, B}, Title = {How Dense Does Parton Matter Get in Pb + Pb Collisions at the CERN SPS?}, Journal = {Acta Physica Hungarica New Series Heavy Ion Physics}, Volume = {7}, Number = {2}, Pages = {207-213}, Year = {1998}, url = {http://arxiv.org/pdf/nucl-th/9707048}, Abstract = {We examine the qualitative features of parton production through materialization in heavy-ion collisions within perturbative QCD, and estimate the magnitude of the resulting parton density created during the early stage of the collisions. The implications for "anomalous" J/ψ suppression observed in Pb + Pb collisions at the CERN SPS are discussed. We argue that the A-dependence of absorption of J/ψ by (partonic) comovers is steeper than assumed in most phenomenological models, because the absorption process is dominated by quasi-perturbative QCD interactions. Our argument is supported by results recently obtained in the framework of the parton cascade model. We predict significant "anomalous" suppression for Pb + Pb collisions at the CERN-SPS, but not for S + U collisions.}, Key = {Geiger:1998ct} } @article{Matinyan:1998ps, Author = {Matinyan, SG and Müller, B and Rischke, DH}, Title = {Classical gluon radiation in ultrarelativistic nuclear collisions: Space-time structure, instabilities, and thermalization}, Journal = {Physical Review C - Nuclear Physics}, Volume = {57}, Number = {4}, Pages = {1927-1937}, Year = {1998}, url = {http://arxiv.org/pdf/nucl-th/9708053}, Abstract = {We investigate the space-time structure of the classical gluon field produced in an ultrarelativistic collision between color charges. The classical solution which was computed previously in a perturbative approach is shown to become unstable on account of the non-Abelian self-interaction neglected in the perturbative solution scheme. The time scale for growth of the instabilities is found to be of the order of the distance between the colliding color charges. We argue that these instabilities will eventually lead to thermalization of gluons produced in an ultrarelativistic collision between heavy nuclei. The rate of thermalization is estimated to be of order g2μ, where g is the strong coupling constant and μ2 the transverse color charge density of an ultrarelativistic nucleus.}, Key = {Matinyan:1998ps} } @article{Moore:1998sn, Author = {Moore, GD and Hu, C and uuml, M and ller, B}, Title = {Chern-Simons number diffusion with hard thermal loops}, Journal = {Phys. Rev. D}, Volume = {58}, Number = {4}, Pages = {045001}, Year = {1998}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-ph/9710436}, Abstract = {http://arxiv.org/abs/hep-ph/9710436}, Key = {Moore:1998sn} } @article{Asakawa:1998st, Author = {Asakawa, M and Minakata, H and uuml, M and ller, B}, Title = {Anomaly induced domain formation of disoriented chiral condensates}, Journal = {Phys. Rev. D}, Volume = {58}, Number = {9}, Pages = {094011}, Year = {1998}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-ph/9805261}, Abstract = {http://arxiv.org/abs/hep-ph/9805261}, Key = {Asakawa:1998st} } @article{Matinyan:1998cb, Author = {Matinyan, SG and Müller, B}, Title = {Model of charmonium absorption by light mesons}, Journal = {Physical Review C - Nuclear Physics}, Volume = {58}, Number = {5}, Pages = {2994-2997}, Year = {1998}, url = {http://arxiv.org/pdf/nucl-th/9806027}, Abstract = {We calculate the cross sections for dissociation of J/ψ by pions and ρ mesons within the framework of a meson exchange model. We find that these cross sections are small at center-of-mass energies less than 1 GeV above threshold, and that dissociation rates are less than 0.01 fm/c in a thermal meson gas at temperatures where such a description makes sense.}, Key = {Matinyan:1998cb} } @article{fds304589, Author = {Moore, GD and Hu, C and Müller, B}, Title = {Chern-Simons number diffusion with hard thermal loops}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {58}, Number = {4}, Pages = {450011-4500124}, Year = {1998}, ISSN = {0556-2821}, Abstract = {We construct an extension of the standard Kogut-Susskind lattice model for classical (3+ 1)-dimensional Yang-Mills theory, in which "classical particle" degrees of freedom are added. We argue that this will correctly reproduce the "hard thermal loop" effects of hard degrees of freedom, while giving a local implementation which is numerically tractable. We prove that the extended system is Hamiltonian and has the same thermodynamics as dimensionally reduced hot Yang-Mills theory put on a lattice. We present a numerical update algorithm and study the Abelian theory to verify that the classical gauge theory self-energy is correctly modified. Then we use the extended system to study the diffusion constant for the Chern-Simons number. We verify the Arnold-Son-Yaffe picture that the diffusion constant is inversely proportional to the hard thermal loop strength. Our numbers correspond to a diffusion constant of Γ = 29±6α5wT4 for m2D= 11g2T2/6.}, Key = {fds304589} } @article{fds304605, Author = {Asakawa, M and Minakata, H and Müller, B}, Title = {Anomaly induced domain formation of disoriented chiral condensates}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {58}, Number = {9}, Pages = {940111-9401114}, Year = {1998}, ISSN = {0556-2821}, Abstract = {We discuss the effect of the chiral anomaly as a possible mechanism for triggering the formation of domains of disoriented chiral condensate (DCC) in relativistic heavy ion collisions. The anomalous π0→2γ coupling and the strong, Lorentz contracted electromagnetic fields of the heavy ions combine to produce the "anomaly kick" to the field configuration of the neutral pion field. We implement the effect of the anomaly kick in our numerical simulation of the linear sigma model in a schematic way which preserves its characteristic features: the effect is coherent over a large region of space but is opposite in sign above and below the ion scattering plane. We demonstrate by detailed simulations with longitudinal expansion that the DCC domain formation is dramatically enhanced by the anomaly kick in spite of its small absolute magnitude. We examine the behavior of various physical quantities such as pion fields, the axial vector currents, and their correlation functions. Our results also provide useful insight into the mechanism and properties of DCC domain formation, in general. Finally, we discuss some experimental observables which can signal the anomaly induced formation of DCC.}, Key = {fds304605} } @article{Matinyan:1997ya, Author = {Matinyan, SG and Müller, B and Rischke, DH}, Title = {Gluon radiation and coherent states in ultrarelativistic nuclear collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {56}, Number = {4}, Pages = {2191-2201}, Year = {1997}, url = {http://arxiv.org/pdf/nucl-th/9705024}, Abstract = {We explore the correspondence between classical gluon radiation and quantum radiation in a coherent state for gluons produced in ultrarelativistic nuclear collisions. The expectation value of the invariant momentum distribution of gluons in the coherent state is found to agree with the gluon number distribution obtained classically from the solution of the Yang-Mills equations. A criterion for the applicability of the coherent state formalism to the problem of radiation in ultrarelativistic nucleus-nucleus collisions is discussed. This criterion is found to be fulfilled for midrapidity gluons with perturbative transverse momenta larger than ∼ 1-2 GeV and produced in collisions between valence partons.}, Key = {Matinyan:1997ya} } @article{Greiner:1997dx, Author = {Greiner, C and Müller, B}, Title = {Classical fields near thermal equilibrium}, Journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, Volume = {55}, Number = {2}, Pages = {1026-1046}, Year = {1997}, url = {http://arxiv.org/pdf/hep-th/9605048}, Abstract = {We discuss the classical limit for the long-distance ("soft") modes of a quantum field when the hard modes of the field are in thermal equilibrium. We address the question of the correct semiclassical dynamics when a momentum cutoff |p|≤kc≤T is introduced. Higher order contributions lead to a stochastic interpretation for the effective action in analogy with quantum Brownian motion, resulting in dissipation and decoherence for the evolution of the soft modes. Particular emphasis is put on the understanding of dissipation. Our discussion focuses mostly on scalar fields, but we make some remarks on the extension to gauge theories.}, Key = {Greiner:1997dx} } @article{Srivastava:1997rz, Author = {Srivastava, DK and Mustafa, MG and Müller, B}, Title = {Chemical equilibration of an expanding quark-gluon plasma}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {396}, Number = {1-4}, Pages = {45-49}, Year = {1997}, url = {http://arxiv.org/pdf/hep-ph/9608424}, Abstract = {The chemical equilibration of the parton distribution in collisions of two heavy nuclei at the CERN Large Hadron Collider is investigated. Initial conditions are obtained from a self-screened parton cascade calculation. The onset of transverse expansion of the system is found to impede the chemical equilibration. The system initially approaches chemical equilibrium, but then is driven away from it, when the transverse velocity becomes large. © 1997 Elsevier Science B.V.}, Key = {Srivastava:1997rz} } @article{Heinz:1997wx, Author = {Heinz, U and Hu, CR and Leupold, S and Matinyan, SG and Müller, B}, Title = {Thermalization and Lyapunov exponents in Yang-Mills-Higgs theory}, Journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, Volume = {55}, Number = {4}, Pages = {2464-2476}, Year = {1997}, url = {http://arxiv.org/pdf/hep-th/9608181}, Abstract = {We investigate thermalization processes occurring at different time scales in the Yang-Mills-Higgs system at high temperatures. We determine the largest Lyapunov exponent associated with the gauge fields and verify its relation to the perturbatively calculated damping rate of a static gauge boson.}, Key = {Heinz:1997wx} } @article{Matinyan:1997hd, Author = {Matinyan, SG and Müller, B}, Title = {Quantum Fluctuations and Dynamical Chaos: An Effective Potential Approach}, Journal = {Foundations of Physics}, Volume = {27}, Number = {9}, Pages = {1237-1255}, Year = {1997}, url = {http://arxiv.org/pdf/hep-th/9610233}, Abstract = {We discuss the intimate connection between the chaotic dynamics of a classical field theory and the instability of the one-loop effective action of the associated quantum field theory. Using the example of massless scalar electrodynamics, we show how the radiatively induced spontaneous symmetry breaking stabilizes the vacuum state against chaos, and we speculate that monopole condensation can have the same effect in non-Abelian gauge theories.}, Key = {Matinyan:1997hd} } @article{Hu:1997sf, Author = {Hu, CR and Müller, B}, Title = {Classical lattice gauge fields with hard thermal loops}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {409}, Number = {1-4}, Pages = {377-381}, Year = {1997}, url = {http://arxiv.org/pdf/hep-ph/9611292}, Abstract = {We propose a formulation of the long-distance dynamics of gauge theories at finite temperature on a lattice in Minkowski space, including the effects of hard thermal loops on the dynamics of the long wavelength modes. Our approach is based on the dual classical limits of quantum fields as waves and particles in the infrared and ultraviolet limits, respectively. It exhibits manifest invariance under space-dependent lattice gauge transformations and conserves Gauss' law. © 1997 Elsevier Science B.V.}, Key = {Hu:1997sf} } @article{Srivastava:1997qd, Author = {Srivastava, DK and Mustafa, MG and Müller, B}, Title = {Expanding quark-gluon plasmas: Transverse flow, chemical equilibration, and electromagnetic radiation}, Journal = {Physical Review C - Nuclear Physics}, Volume = {56}, Number = {2}, Pages = {1064-1074}, Year = {1997}, url = {http://arxiv.org/pdf/nucl-th/9611041}, Abstract = {We investigate the chemical equilibration of the parton distributions in collisions of two heavy nuclei. We use initial conditions obtained from a self-screened parton cascade calculation and, for comparison, from the HIJING model. We consider a one-dimensional as well as a three-dimensional expansion of the parton plasma and find that the onset of the transverse expansion impedes the chemical equilibration. At energies of 100 GeV/nucleon, the results for one-dimensional and three-dimensional expansions are quite similar except at large values of the transverse radius. At energies of several TeV/nucleon, the plasma initially approaches chemical equilibrium, but then is driven away from it, when the transverse velocity gradients develop. We find that the total parton multiplicity density remains essentially unaffected by the flow, but the individual concentrations of quarks, antiquarks, and gluons are sensitive to the transverse flow. The consequences of the flow are also discernible in the transverse momenta of the partons and in the lepton pair spectra, where the flow causes a violation of the so-called MT scaling.}, Key = {Srivastava:1997qd} } @article{Matinyan:1997rd, Author = {Matinyan, SG and Müller, B}, Title = {Quantum fluctuations and dynamical chaos}, Journal = {Physical Review Letters}, Volume = {78}, Number = {13}, Pages = {2515-2518}, Year = {1997}, url = {http://prola.aps.org/pdf/PRL/v78/i13/p2515_1}, Abstract = {We discuss the intimate connection between the chaotic dynamics of a classical field theory and the instability of the one-loop effective action of the associated quantum field theory. Using massless scalar electrodynamics as an example, we show how the radiatively induced spontaneous symmetry breaking stabilizes the vacuum state against chaos.}, Key = {Matinyan:1997rd} } @article{fds247220, Author = {Müller, B}, Title = {Strangeness in paradise: The strange quark as a probe of QCD}, Journal = {Acta Physica Hungarica New Series Heavy Ion Physics}, Volume = {4}, Number = {1-4}, Pages = {1-14}, Year = {1996}, Abstract = {I review the arguments for considering the strange quark as a probe of changes in the QCD vacuum, and of the formation of a quark-gluon plasma, in particular. I survey existing data showing enhanced production of strange hadrons in relativistic heavy ion collisions and analyse their implications in the context of thermal and microscopic reaction models. My lecture closes with some remarks on strange quark matter and hypernuclei. © 1996 Akadémiai Kiadó, Budapest.}, Key = {fds247220} } @article{Harris:1996zx, Author = {Harris, JW and Müller, B}, Title = {The search for the quark-gluon plasma}, Journal = {Annual Review of Nuclear and Particle Science}, Volume = {46}, Number = {1}, Pages = {71-107}, Year = {1996}, ISSN = {0163-8998}, url = {http://arxiv.org/pdf/hep-ph/9602235}, Abstract = {We provide an overview of the present understanding of the transition from hadrons to a quark-gluon plasma, its signatures, and the experimental results so far. We discuss results of numerical simulations of the lattice gauge theory and critically evaluate the various observables that have been proposed as signatures of the QCD phase transition. We place the existing data from relativistic heavy-ion experiments at the Brookhaven Alternating Gradient Synchrotron (AGS) and CERN Super Proton Synchrotron (SPS) into perspective and provide an overview of the techniques and strategies that will be employed in the search for the quark-gluon plasma at heavy-ion colliders, such as the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC).}, Key = {Harris:1996zx} } @article{Hu:1996ar, Author = {Hu, CR and Matinyan, SG and Müller, B}, Title = {Symmetry restoration in gauge boson wave packet collisions in Yang-Mills-Higgs theory}, Journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, Volume = {54}, Number = {3}, Pages = {2175-2181}, Year = {1996}, url = {http://arxiv.org/pdf/hep-ph/9603434}, Abstract = {We investigate the restoration of spontaneously broken gauge symmetry in collisions of gauge boson wave packets in the SU(2) Higgs model.}, Key = {Hu:1996ar} } @article{Rau:1996ea, Author = {Rau, J and Müller, B}, Title = {From reversible quantum microdynamics to irreversible quantum transport}, Journal = {Physics Report}, Volume = {272}, Number = {1}, Pages = {1-59}, Year = {1996}, url = {http://arxiv.org/pdf/nucl-th/9505009}, Abstract = {The transition from reversible microdynamics to irreversible transport can be studied very efficiently and systematically with the help of the so-called projection method. After a concise introduction to that method we illustrate its power by using it to analyze the well-known rate and quantum Boltzmann equations, and we present, as a new application, the derivation of a source term which accounts for the spontaneous creation of electron-positron pairs in strong fields. Thereby we emphasize the pivotal role of time scales: Only if the various time scales exhibited by the dynamics are widely disparate can the evolution of the slower degrees of freedom be described by a conventional Markovian transport equation; otherwise one must account for finite memory effects. We show how the projection method can be employed to determine these time scales and how - if necessary - it allows one to include memory effects in a straightforward manner. There is also an appendix in which we discuss the concepts of entropy and macroscopic irreversibility.}, Doi = {10.1016/0370-1573(95)00077-1}, Key = {Rau:1996ea} } @article{Eskola:1996bp, Author = {Eskola, KJ and Müller, B and Wang, X-N}, Title = {Screening of initial parton production in ultrarelativistic heavy-ion collisions}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {374}, Number = {1-3}, Pages = {20-24}, Year = {1996}, url = {http://arxiv.org/pdf/hep-ph/9509285}, Abstract = {Screening of initial parton production due to the presence of on-shell partons in high-energy heavy-ion collisions is discussed. It is shown that the divergent cross sections in the calculation of parton production can be regulated self-consistently without an ad hoc cut-off, and that the resultant parton production and transverse energy production rate are finite.}, Key = {Eskola:1996bp} } @article{Hu:1996kd, Author = {Hu, CR and Matinyan, SG and Müller, B and Sweet, D}, Title = {Wave packet collisions in Yang-Mills-Higgs theory}, Journal = {Physical Review D - Particles, Fields, Gravitation and Cosmology}, Volume = {53}, Number = {7}, Pages = {3823-3834}, Year = {1996}, url = {http://arxiv.org/pdf/hep-ph/9509305}, Abstract = {We present numerical simulations of colliding wave packets in spontaneously broken SU(2) Yang-Mills-Higgs theory. Compared with pure Yang-Mills theory, introducing the Higgs field leads to new aspects in the dynamics of the system. The evolution of the gauge field and the Higgs field is investigated as a function of the amplitude of the wave packets and of the mass ratio of the Higgs boson and the gauge boson. We find regions in our parameter space in which initial wave packets scatter into final configurations with dramatically different momentum distributions.}, Key = {Hu:1996kd} } @article{Minakata:1996gq, Author = {Minakata, H and Müller, B}, Title = {Disoriented chiral condensate and strong electromagnetic fields}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {377}, Number = {1-3}, Pages = {135-139}, Year = {1996}, url = {http://arxiv.org/pdf/hep-ph/9511348}, Abstract = {We discuss the effect of strong electromagnetic fields on chiral orientation in the framework of the linear σ model. Based on lessons we learn from computation of the effective potential at one loop, we argue that the chiral U(1) anomaly dominates chiral disorientation driven by electromagnetism. We show that the anomaly effect induces a quasi-instantaneous "kick" to field configurations along the π0 direction in relativistic heavy-ion collisions. We discuss the possibility that a "kick", even though small in magnitude, can have a substantial effect on the formation of chirally misaligned domains.}, Key = {Minakata:1996gq} } @article{fds247219, Author = {Müller, B}, Title = {Quark matter '95: Where are we and what needs to be done?}, Journal = {Nuclear Physics A}, Volume = {590}, Number = {1-2}, Pages = {3-10}, Year = {1995}, ISSN = {0375-9474}, Key = {fds247219} } @article{Hu:1995ia, Author = {Hu, CR and Matinyan, SG and Müller, B and Trayanov, A and Gould, TM and Hsu, SDH and Poppitz, ER}, Title = {Wave packet dynamics in Yang-Mills theory}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {52}, Number = {4}, Pages = {2402-2411}, Year = {1995}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-ph/9502276}, Abstract = {We discuss the results of numerical simulations of colliding wave packets in SU(2) Yang-Mills theory. We investigate their behavior as a function of amplitude and momentum distribution. We find regions in our parameter space in which initial wave packets scatter into final configurations with dramatically different momentum distributions. These results constitute new classical trajectories with multiparticle boundary conditions. We explain their relevance for the calculation of scattering amplitudes in the semiclassical approximation. Finally, we give directions for future work. © 1995 The American Physical Society.}, Doi = {10.1103/PhysRevD.52.2402}, Key = {Hu:1995ia} } @article{Mrowczynski:1995at, Author = {Mrówczyński, S and Müller, B}, Title = {Reheating after supercooling in the chiral phase transition}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {363}, Number = {1-2}, Pages = {1-4}, Year = {1995}, url = {http://arxiv.org/pdf/nucl-th/9507033}, Abstract = {We study the conversion of the latent heat of a supercooled quark-gluon plasma into excitations of the pion field. Supercooling is predicted to occur in the late stages of the evolution of a quark-gluon plasma produced in energetic heavy-ion collisions, if the QCD phase transition is of first order. The supercooled, chirally symmetric state, which contains potential energy associated with an energetically unfavorable field configuration, eventually rolls down to the true minimum of the effective chiral potential. When this motion is described in terms of the linear sigma-model, we find that the energy of the coherent σ-field is very efficiently converted into pionic excitations due to anharmonic oscillations around the minimum. The system is expected to partially thermalize before its disintegration.}, Key = {Mrowczynski:1995at} } @article{Biro:1995sh, Author = {Biró, TS and Matinyan, SG and Müller, B}, Title = {Chaos driven by soft-hard mode coupling in thermal Yang-Mills theory}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {362}, Number = {1-4}, Pages = {29-33}, Year = {1995}, Abstract = {We argue on a basis of a simple few modes model of SU(2) Yang-Mills theory that the color off-diagonal coupling of the soft plasmon to hard thermal excitations of the gauge field drives the collective plasma oscillations into chaotic motion despite the presence of the plasmon mass.}, Key = {Biro:1995sh} } @article{Biro:1995hs, Author = {Biró, TS and Gong, C and Müller, B}, Title = {Lyapunov exponent and plasmon damping rate in non-Abelian gauge theories}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {52}, Number = {2}, Pages = {1260-1266}, Year = {1995}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-ph/9409392}, Abstract = {We explain why the maximal positive Lyapunov exponent of classical SU(N) gauge theory coincides with (twice) the damping rate of a plasmon at rest in the leading order of thermal gauge theory. © 1995 The American Physical Society.}, Doi = {10.1103/PhysRevD.52.1260}, Key = {Biro:1995hs} } @article{Muller:1995rb, Author = {Müller, B}, Title = {Physics and signatures of the quark-gluon plasma}, Journal = {Reports on Progress in Physics}, Volume = {58}, Number = {6}, Pages = {611-636}, Year = {1995}, ISSN = {0034-4885}, url = {http://arxiv.org/pdf/nucl-th/9410005}, Abstract = {This is a critical review of the various observables that have been proposed to signal the change from dense hadronic matter to a quark-gluon plasma at high temperature or baryon density. I discuss current models of quark-gluon plasma formation in relativistic heavy-ion collisions and analyse the virtues and ambiguities of various signatures.}, Doi = {10.1088/0034-4885/58/6/002}, Key = {Muller:1995rb} } @article{Schramm:1995cd, Author = {Schramm, AJ and Müller, B}, Title = {Pion fusion in peripheral pp collisions}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {52}, Number = {11}, Pages = {6616-6619}, Year = {1995}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-ph/9410402}, Abstract = {We estimate the cross section for quasielastic double pion exchange in high energy proton-proton collisions. Total and elastic ππ cross sections are calculated in an equivalent pion approximation, with pion-baryon vertices taken from chiral perturbation theory. © 1995 The American Physical Society.}, Doi = {10.1103/PhysRevD.52.6616}, Key = {Schramm:1995cd} } @article{Levai:1995dx, Author = {Lévai, P and Müller, B and Wang, X-N}, Title = {Open charm production in an equilibrating parton plasma}, Journal = {Physical Review C - Nuclear Physics}, Volume = {51}, Number = {6}, Pages = {3326-3335}, Year = {1995}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/hep-ph/9412352}, Abstract = {Open charm production during the equilibration of a gluon dominated parton plasma is calculated, with both the time-dependent temperature and parton densities given by a set of rate equations. Including prethermal production, the total enhancement of open charm production over the initial gluon fusion depends sensitively on the initial parton density and the effective temperature. The dependence of the prethermal charm production on the space-momentum correlation in the initial parton phase-space distribution is also discussed. © 1995 The American Physical Society.}, Doi = {10.1103/PhysRevC.51.3326}, Key = {Levai:1995dx} } @article{fds247217, Author = {Biró, TS and Müller, B and Thoma, MH and Wang, XN}, Title = {Parton equilibration at RHIC and LHC}, Journal = {Nuclear Physics A}, Volume = {566}, Number = {C}, Pages = {543-546}, Year = {1994}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/0375-9474(94)90689-0}, Abstract = {The processes leading to phase space equilibration of parton distributions in ultrarelativistic heavy ion collisions are investigated. A set of rate equations describing the chemical equilibration of quarks and gluons based on perturbative QCD including medium effects are derived, and their consequences for parton equilibration at RHIC and LHC are discussed. © 1994.}, Doi = {10.1016/0375-9474(94)90689-0}, Key = {fds247217} } @article{fds247218, Author = {Xin-Nian, W and Müller, B}, Title = {D-meson as a probe of early parton rescattering}, Journal = {Nuclear Physics A}, Volume = {566}, Number = {C}, Pages = {555-558}, Year = {1994}, ISSN = {0375-9474}, Abstract = {Initial parton scatterings produce a hot and dilute gluonic gas in high energy nuclear collisions. Pre-equilibrium gluon rescatterings are shown to have significant contributions to the charm production. In contrast to the gluon shadowing effect in the initial parton scattering, the enhancement of the final total open charm in the central region due to pre-equilibrium production could be used as a probe of the early dynamics of the partonic system. © 1994.}, Key = {fds247218} } @article{Geiger:1994dt, Author = {Geiger, K and uuml, M and ller, B}, Title = {QCD evolution equations for high-energy partons in nuclear matter}, Journal = {Phys. Rev. D}, Volume = {50}, Pages = {337-357}, Year = {1994}, url = {http://arxiv.org/pdf/hep-ph/9312281}, Abstract = {http://arxiv.org/abs/hep-ph/9312281}, Key = {Geiger:1994dt} } @article{Mrowczynski:1994nf, Author = {Mrwczyński, S and Müller, B}, Title = {Wigner functional approach to quantum field dynamics}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {50}, Number = {12}, Pages = {7542-7552}, Year = {1994}, ISSN = {0556-2821}, url = {http://arxiv.org/pdf/hep-th/9405036}, Abstract = {We introduce the Wigner functional representing a quantum field in terms of the field amplitudes and their conjugate momenta. The equation of motion for the functional of a scalar field points out the relevance of solutions of the classical field equations to the time evolution of the quantum field. We discuss the field in thermodynamical equilibrium and find the explicit solution of the equations of motion for the so-called rollover phase transition. Finally, we briefly discuss the approximate methods for the evaluation of the Wigner functional that may be used to numerically simulate the initial value problem. © 1994 The American Physical Society.}, Doi = {10.1103/PhysRevD.50.7542}, Key = {Mrowczynski:1994nf} } @article{Gong:1994fz, Author = {Gong, C and Müller, B and Biró, TS}, Title = {Variational approach to real-time evolution of Yang-Mills gauge fields on the lattice}, Journal = {Nuclear Physics A}, Volume = {568}, Number = {4}, Pages = {727-744}, Year = {1994}, ISSN = {0375-9474}, url = {http://arxiv.org/pdf/hep-lat/9305024}, Abstract = {Applying a variational method to a gaussian wave ansatz, we have derived a set of semi-classical evolution equations for SU(2) lattice gauge fields, which take the classical form in the limit of a vanishing width of the gaussian wave packet. These equations are used to study the quantum effects on the classical evolutions of the lattice gauge fields. © 1994.}, Key = {Gong:1994fz} } @article{Biro:1994qc, Author = {Biro, TS and Gong, C and uuml, M and ller, B and Trayanov, A}, Title = {Hamiltonian dynamics of Yang-Mills fields on a lattice}, Journal = {Int. J. Mod. Phys. C}, Volume = {5}, Pages = {113-149}, Year = {1994}, url = {http://arxiv.org/pdf/nucl-th/9306002}, Abstract = {http://arxiv.org/abs/nucl-th/9306002}, Key = {Biro:1994qc} } @article{Gong:1994bz, Author = {Gong, C and Matinyan, SG and uuml, M and ller, B and Trayanov, A}, Title = {Manifestation of infrared instabilities in high-energy processes in nonAbelian gauge theories}, Journal = {Phys. Rev. D}, Volume = {49}, Pages = {607-610}, Year = {1994}, url = {http://arxiv.org/pdf/nucl-th/9310001}, Abstract = {http://arxiv.org/abs/nucl-th/9310001}, Key = {Gong:1994bz} } @article{Gavin:1994px, Author = {Gavin, S and Müller, B}, Title = {Larger domains of disoriented chiral condensate through annealing}, Journal = {Physics Letters B}, Volume = {329}, Number = {4}, Pages = {486-492}, Year = {1994}, ISSN = {0370-2693}, url = {http://arxiv.org/pdf/hep-ph/9312349}, Abstract = {Relativistic heavy ion collisions can generate metastable domains in which the chiral condensate is disoriented. Nucleussizeddomains can yield measurable fluctuations in the number of neutral and charged pions. We propose a scenario in whichdomains are "annealed" by a dynamically evolving effective potential in the heavy ion system. Domains of sizes exceeding3 fm are possible in this scenario. © 1994.}, Doi = {10.1016/0370-2693(94)91094-4}, Key = {Gavin:1994px} } @article{art109, Author = {Ionescu, DC and Greiner, W and Muller, B and Soff, G}, Title = {Collective excitations of the QED vacuum}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {47}, Number = {2}, Pages = {854-867}, Year = {1993}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.47.854}, Abstract = {Using relativistic Green's-function techniques we examined single-electron excitations from the occupied Dirac sea in the presence of strong external fields. The energies of these excited states are determined taking into account the electron-electron interaction. We also evaluate relativistic transition strengths incorporating retardation, which represents a direct measure of correlation effects. The shifts in excitation energies are computed to be lower than 0.5%, while the correlated transition strengths never deviate by more than 10% from their bare values. A major conclusion is that we found no evidence for collectivity in the electron-positron field around heavy and superheavy nuclei. © 1993 The American Physical Society.}, Doi = {10.1103/PhysRevA.47.854}, Key = {art109} } @article{Biro:1993qt, Author = {Biró, TS and Doorn, EV and Müller, B and Thoma, MH and Wang, X-N}, Title = {Parton equilibration in relativistic heavy ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {48}, Number = {3}, Pages = {1275-1284}, Year = {1993}, ISSN = {0556-2813}, url = {http://arxiv.org/pdf/nucl-th/9303004}, Abstract = {We investigate the processes leading to phase-space equilibration of parton distributions in nuclear interactions at collider energies. We derive a set of rate equations describing the chemical equilibration of gluons and quarks including medium effects on the relevant QCD transport coefficients, and discuss their consequences for parton equilibration in heavy ion collisions. © 1993 The American Physical Society.}, Doi = {10.1103/PhysRevC.48.1275}, Key = {Biro:1993qt} } @article{Greiner:1993jn, Author = {Greiner, C and Gong, C and uuml, M and ller, B}, Title = {Some remarks on pion condensation in relativistic heavy ion collisions}, Journal = {Phys. Lett. B}, Volume = {316}, Number = {2-3}, Pages = {226-230}, Year = {1993}, ISSN = {0370-2693}, url = {http://arxiv.org/pdf/hep-ph/9307336}, Abstract = {http://arxiv.org/abs/hep-ph/9307336}, Doi = {10.1016/0370-2693(93)90317-B}, Key = {Greiner:1993jn} } @article{Biedenharn:1993xk, Author = {Biedenharn, LC and Mueller, B and Tarlini, M}, Title = {The Dirac-Coulomb problem for the κ-Poincar e ́ quantum group}, Journal = {Physics Letters B}, Volume = {318}, Number = {4}, Pages = {613-616}, Year = {1993}, ISSN = {0370-2693}, url = {http://arxiv.org/pdf/hep-th/9310173}, Abstract = {The recently introduced κ-Poincar e ́-Dirac equation is gauged to treat the κ-Dirac-Coulomb problem. For the resulting equation, we prove that the perturbation to first order in the quantum group parameter vanishes identically. The second order perturbation is singular, but assuming a heuristic cut-off allows a qualitative estimate of the quantum group parameter. © 1993.}, Doi = {10.1016/0370-2693(93)90462-Q}, Key = {Biedenharn:1993xk} } @article{Biro:1993wg, Author = {Biró, TS and Müller, B}, Title = {Magnetic screening in thermal Yang-Mills theories}, Journal = {Nuclear Physics A}, Volume = {561}, Number = {4}, Pages = {477-500}, Year = {1993}, ISSN = {0375-9474}, url = {http://arxiv.org/pdf/nucl-th/9211011}, Abstract = {We develop a method to calculate the density of magnetic monopoles in nonabelian gauge theories at finite temperature in the dilute gas approximation in the semiclassical limit. This quantity is related to the inverse magnetic screening length for which we obtain μM = 0.255g2T in SU(2). © 1993.}, Doi = {10.1016/0375-9474(93)90061-2}, Key = {Biro:1993wg} } @article{fds304588, Author = {Greiner, C and Gong, C and Müller, B}, Title = {Pion condensation in relativistic heavy ion collisions}, Journal = {Physics Letters B}, Volume = {316}, Number = {2-3}, Pages = {226-230}, Year = {1993}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(93)90317-B}, Abstract = {Recently it was pointed out that coherent or condensated states of pions may account for the explanation of the Centauro events observed in cosmic ray showers. We argue that an occurence of condensed pions requires that the system evolves far out of thermal equilibrium. Besides an unusual charge ratio distribution we show that such a produced state also would lead to strong isospin correlations. © 1993.}, Doi = {10.1016/0370-2693(93)90317-B}, Key = {fds304588} } @article{fds247215, Author = {Müller, B}, Title = {Signatures of the quark-gluon plasma}, Journal = {Nuclear Physics A}, Volume = {544}, Number = {1-2}, Pages = {95-108}, Year = {1992}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/0375-9474(92)90567-4}, Abstract = {I review the various observables that have been proposed as signals for the change in the structure of dense hadronic matter, when it becomes quark-gluon plasma at high temperature, or quark matter at high baryon density. I also discuss the inherent ambiguities of these signatures. © 1992.}, Doi = {10.1016/0375-9474(92)90567-4}, Key = {fds247215} } @article{Muller:1992xn, Author = {uuml, M and ller, B and Wang, X-N}, Title = {Probing parton thermalization time with charm production}, Journal = {Phys. Rev. Lett.}, Volume = {68}, Pages = {2437-2439}, Year = {1992}, Key = {Muller:1992xn} } @article{Muller:1992iw, Author = {Müller, B and Trayanov, A}, Title = {Deterministic chaos in non-Abelian lattice gauge theory}, Journal = {Physical Review Letters}, Volume = {68}, Number = {23}, Pages = {3387-3390}, Year = {1992}, ISSN = {0031-9007}, Abstract = {We present numerical evidence that the real-time Hamiltonian dynamics of SU(2) gauge theory on a spatial lattice exhibits deterministic chaos in the semiclassical limit. We determine the largest Lyapunov exponent of the gauge field as a function of energy density, and derive a nonperturbative expression for the thermalization time.}, Key = {Muller:1992iw} } @article{Biro:1992ix, Author = {Biró, TS and Müller, B and Wang, X-N}, Title = {Color screening in relativistic heavy ion collisions}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {283}, Number = {3-4}, Pages = {171-173}, Year = {1992}, Abstract = {We calculate the color screening length in a non-equilibrated gluon gas formed by interacting minijets in relativistic heavy-ion collisions. We show that that the screening length is too short at CERN LHC collider energy to permit the formation of independent flux-tubes or strings. The prediction for RHIC energies is somewhat ambiguous.}, Key = {Biro:1992ix} } @article{Muller:1992qc, Author = {Müller, B and Thoma, MH}, Title = {Vacuum polarization and the electric charge of the positron}, Journal = {Physical Review Letters}, Volume = {69}, Number = {24}, Pages = {3432-3434}, Year = {1992}, ISSN = {0031-9007}, url = {http://arxiv.org/pdf/hep-ph/9209217}, Abstract = {We show that higher-order vacuum polarization would contribute a measurable net charge to atoms, if the charges of electrons and positrons do not balance precisely. We obtain the limit |Qe + Qē| < 10-18e for the sum of the charges of electron and positron. This also constitutes a new bound on certain violations of PCT invariance.}, Key = {Muller:1992qc} } @article{Dean:1992vj, Author = {Dean, DJ and Gyulassy, M and Müller, B and Remler, EA and Strayer, MR and Umar, AS and Wu, J-S}, Title = {Multiparticle production in lepton-nucleus collisions and relativistic string models}, Journal = {Physical Review C - Nuclear Physics}, Volume = {46}, Number = {5}, Pages = {2066-2076}, Year = {1992}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.46.2066}, Abstract = {Nuclear attenuation of the leading (xf>0) hadron and the nuclear enhancement of target fragmentation (xf<0) hadrons in lepton-nucleus reactions are calculated via a (3+1)-dimensional string-parton model. A (1+1)-dimensional string model is used to investigate the dependence of rapidity distributions on the lepton energy loss, =10100 GeV, the atomic number, A=1200, the effective string tension, =0.52 GeV/fm, the string decay constant, 0=0.52 fm/c, and the string flip cross section, lq=030 mb. The (3+1)-dimensional string-parton model includes inelastic final state cascading of produced hadrons in the nucleus. We show how the A dependence of hadronic production in lepton-nucleus collisions, especially in the xf<0 region, may be used to extract information on quark propagation and hadronization in nuclei. © 1992 The American Physical Society.}, Doi = {10.1103/PhysRevC.46.2066}, Key = {Dean:1992vj} } @article{Schramm:1992ex, Author = {Schramm, S and uuml, M and ller, B and Schramm, AJ}, Title = {Quark - anti-quark condensates in strong magnetic fields}, Journal = {Mod. Phys. Lett. A}, Volume = {7}, Pages = {973-982}, Year = {1992}, Key = {Schramm:1992ex} } @article{Abou-El-Naga:1992ib, Author = {Abou-El-Naga, N and Geiger, K and Muller, B}, Title = {QCD phenomenology of nucleon-nucleon cross sections}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {18}, Number = {5}, Pages = {797-805}, Year = {1992}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/18/5/009}, Abstract = {The authors calculate the inclusive parton-parton cross section in p+p and p+p collisions in the framework of perturbative QCD and snow that the measured non-diffractive cross section requires a transverse momentum cut-off p Tmin of several GeV c-1 at high energy. They consider the implications for nuclear collisions at RHIC and LHC energies.}, Doi = {10.1088/0954-3899/18/5/009}, Key = {Abou-El-Naga:1992ib} } @article{Schramm:1992vt, Author = {Schramm, S and Müller, B and Schramm, AJ}, Title = {W boson condensation in p-p collisions?}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {277}, Number = {4}, Pages = {512-514}, Year = {1992}, Abstract = {We address the question of whether W± boson condensation can occur in high-energy collisions.}, Key = {Schramm:1992vt} } @article{Schramm:1992vu, Author = {Schramm, S and Müller, B and Schramm, AJ}, Title = {Exact Dirac propagator in a magnetic "sheet"}, Journal = {Physics Letters A}, Volume = {164}, Number = {1}, Pages = {28-32}, Year = {1992}, ISSN = {0375-9601}, Abstract = {We derive the exact fermionic Green function in an idealized magnetic field configuration, which becomes exact in the infinite energy limit. The fields under consideration can be produced, e.g., in peripheral ultrarelativistic heavy-ion collisions. © 1992.}, Key = {Schramm:1992vu} } @article{Geiger:1992nj, Author = {Geiger, K and Müller, B}, Title = {Dynamics of parton cascades in highly relativistic nuclear collisions}, Journal = {Nuclear Physics B}, Volume = {369}, Number = {3}, Pages = {600-654}, Year = {1992}, ISSN = {0375-9474}, Abstract = {We present a fully relativistic space-time approach for the simulation of highly-energetic nucleus-nucleus collisions. The model incorporates the idea of the factorization of short-range parton-parton interactions and the hadronization process. The nuclear collisions are described by the time evolution of the parton distributions in phase space according to a relativistic transport-equation with a collision term that embodies the structure of parton-parton collisions and associated parton emission processes as calculated in the framework of perturbative QCD. We have studied A + A collisions from p + p up to 238U + 238U at center-of-mass energies of 100 GeV/A and 200 GeV/A. Results for the time evolution of parton multiplicities, transverse energy production, rapidity and p ⊥ distributions are presented.}, Key = {Geiger:1992nj} } @article{fds318459, Author = {Geiger, K and Müller, B}, Title = {Dynamics of parton cascades in highly relativistic nuclear collisions}, Journal = {Nuclear Physics A}, Volume = {544}, Number = {1-2}, Pages = {467-470}, Year = {1992}, Abstract = {We present a QCD based relativistic kinetic model for high energy nuclear colisions, which is inspired by the parton picture of hadronic interactions. The nuclear dynamics is traced back to the microscopic level of quark and gluon interactions in the framework of perturbative QCD. The time evolution of the nuclear system is described in real time by a relativistic transport equation for the parton distributions that is solved by Monte Carlo methods. © 1992.}, Key = {fds318459} } @article{fds304587, Author = {Scherdin, A and Reinhardt, J and Greiner, W and Müller, B}, Title = {Low-energy e^{+}e^{-}scattering}, Journal = {Reports on Progress in Physics}, Volume = {54}, Number = {1}, Pages = {1-52}, Year = {1991}, ISSN = {0034-4885}, url = {http://dx.doi.org/10.1088/0034-4885/54/1/001}, Abstract = {Electron-positron scattering provides a model-independent test for the existence of neutral particles coupling to the e+e- field. This article reviews the effects of possible particle resonances X0 in the energy range between threshold and a few MeV on electron-positron scattering. The presentation focuses on theoretical aspects, but results of recent precision measurements of Bhabha scattering and e+e- annihilation in flight are also briefly surveyed.}, Doi = {10.1088/0034-4885/54/1/001}, Key = {fds304587} } @article{fds247212, Author = {Müller, B and Schramm, AJ}, Title = {Higgs boson production in heavy ion collisions}, Journal = {Nuclear Physics A}, Volume = {525}, Number = {C}, Pages = {373-377}, Year = {1991}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/0375-9474(91)90348-A}, Abstract = {The idea of producing neutral particles via fusion of virtual photons accompanying ultra-relaitivistic heavy ions is reviewed. In particular, the possibility that such a mechanism could provide a method for producing and detecting intermediate mass Higgs bosons (MZ ≲ MH ≲ 2MW) is discussed. © 1991.}, Doi = {10.1016/0375-9474(91)90348-A}, Key = {fds247212} } @article{fds247213, Author = {Müller, B}, Title = {Strangeness in relativistic heavy ion collisions}, Journal = {Nuclear Physics A}, Volume = {527}, Number = {C}, Pages = {617-620}, Year = {1991}, ISSN = {0375-9474}, Abstract = {Recently studied aspects of the production of strange hadrons in relativistic nuclear collisions and their relevance as a signature of quark-gluon plasma formation are reviewed. © 1991.}, Key = {fds247213} } @article{Levai:1991be, Author = {Lévai, P and Müller, B}, Title = {Transverse baryon flow as possible evidence for a quark-gluon-plasma phase}, Journal = {Physical Review Letters}, Volume = {67}, Number = {12}, Pages = {1519-1522}, Year = {1991}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.67.1519}, Abstract = {In order to investigate the coupling between collective flow of nucleons and pions in hot pion-dominated hadronic matter, we calculate the pion-nucleon drag coefficient in linearized transport theory. We find that the characteristic time for flow equalization is longer than the time scale of the expansion of a hardonic fireball created in high-energy collisions. The analysis of transverse-momentum data from p+p collisions at s =1.8 TeV reveals the same flow velocity for mesons and antinucleons. We argue that this may be evidence for the formation of a quark-gluon plasma in these collisions. © 1991 The American Physical Society.}, Doi = {10.1103/PhysRevLett.67.1519}, Key = {Levai:1991be} } @article{art108, Author = {Plunien, G and Müller, B and Greiner, W and Soff, G}, Title = {Nuclear polarization in heavy atoms and superheavy quasiatoms}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {43}, Number = {11}, Pages = {5853-5866}, Year = {1991}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.43.5853}, Abstract = {We consider the contribution of nuclear polarization to the Lamb shift of K- and L-shell electrons in heavy atoms and quasiatoms. Our formal approach is based on the concept of effective photon propagators with nuclear-polarization insertions treating effects of nuclear polarization on the same footing as usual QED radiative corrections. We explicitly derive the modification of the photon propagator for various collective nuclear excitations and calculate the corresponding effective self-energy shift perturbatively. The energy shift of the 1s1/2 state in U92238 due to virtual excitation of nuclear rotational states is shown to be a considerable correction for atomic high-precision experiments. In contrast to this, nuclear-polarization effects are of minor importance for Lamb-shift studies in Pb82208. © 1991 The American Physical Society.}, Doi = {10.1103/PhysRevA.43.5853}, Key = {art108} } @article{Scherdin:1991xy, Author = {Scherdin, A and Reinhardt, J and Greiner, W and uuml, M and ller, B}, Title = {Low-energy e+ e- scattering}, Journal = {Rept. Prog. Phys.}, Volume = {54}, Number = {1}, Pages = {1-52}, Year = {1991}, ISSN = {0034-4885}, url = {http://dx.doi.org/10.1088/0034-4885/54/1/001}, Abstract = {Electron-positron scattering provides a model-independent test for the existence of neutral particles coupling to the e+e- field. This article reviews the effects of possible particle resonances X0 in the energy range between threshold and a few MeV on electron-positron scattering. The presentation focuses on theoretical aspects, but results of recent precision measurements of Bhabha scattering and e+e- annihilation in flight are also briefly surveyed.}, Doi = {10.1088/0034-4885/54/1/001}, Key = {Scherdin:1991xy} } @article{Muller:1991sg, Author = {Müller, B and Schramm, AJ}, Title = {Higgs boson production in peripheral heavy-ion collisions. Coherent double-pomeron exchange}, Journal = {Nuclear Physics A}, Volume = {523}, Number = {3-4}, Pages = {677-693}, Year = {1991}, ISSN = {0375-9474}, Abstract = {Higgs boson production by coherent double-pomeron exchange in peripheral nuclear collisions at energies of several TeV per nucleon is calculated. It is shown that a trigger on quasi-elastic nuclear collisions strongly suppresses the cross section. The analogous two-photon process is predicted to dominate for collisions of heavy nuclei. © 1991.}, Key = {Muller:1991sg} } @article{Muller:1991yz, Author = {uuml, M and ller, B and Schramm, S}, Title = {Quark gluon plasma signatures?}, Journal = {Phys. Rev.}, Volume = {C43}, Pages = {2791-2797}, Year = {1991}, Key = {Muller:1991yz} } @article{fds322936, Author = {Baier, S and Martins, M and Muller, BR and Schulze, M and Zimmermann, P}, Title = {Investigation of autoionizing levels in the Ag I spectrum populated by a combination of discharge and laser excitation}, Journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, Volume = {23}, Number = {18}, Pages = {3095-3104}, Year = {1990}, Month = {September}, url = {http://dx.doi.org/10.1088/0953-4075/23/18/012}, Doi = {10.1088/0953-4075/23/18/012}, Key = {fds322936} } @article{fds247210, Author = {Geiger, K and Müller, B and Greiner, W}, Title = {(η-η′-ι)-mixing, decay and production mechanisms}, Journal = {Zeitschrift für Physik C-Particles and Fields}, Volume = {48}, Number = {2}, Pages = {257-271}, Year = {1990}, ISSN = {0170-9739}, url = {http://dx.doi.org/10.1007/BF01554474}, Abstract = {We present a phenomenological model for meson-glueball mixing and apply it to the mixing of the pseudoscalar mesons η and η′ with the ι(1440)-particle as the prime candidate for a 0-+-glueball. Using the MIT bag model framework, our model incorporates, among other elements, configuration mixing effects due to virtually excited states, as well as mixing of quark and gluon components. We evaluate the portions of quark antiquark and two-gluon admixtures in η,η′ and ι. The results are used to study various decay and production processes involving these particles. In particular, we calculate the radiative and the 2γ-decay widths of the light mesons and make predictions for the widths of the ι in these channels. Furthermore, production mechanisms of the light mesons in electromagnetic and hadronic J/ψ-decays are used to evaluate the branching ratios for the production of the ι in various J/ψ-transitions. Our results are generally in reasonable agreement with experimental data. Especially we predict a rather large width for the decay ι→ργ and a sizable production rate for the ι in the transition J/ψ→ωι. © 1990 Springer-Verlag.}, Doi = {10.1007/BF01554474}, Key = {fds247210} } @article{Rau:1990fv, Author = {Rau, J and Muller, B and Greiner, W and Soff, G}, Title = {Production of supersymmetric particles in ultrarelativistic heavy-ion collisions}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {16}, Number = {2}, Pages = {211-220}, Year = {1990}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/16/2/010}, Abstract = {Heavy ions with energies of some TeV per nucleon can be considered as carriers of intense photon fields. In peripheral collisions elementary particles with masses up to a few 100 GeV can be produced via two-photon processes. The authors evaluate total cross sections for the formation of charged supersymmetric particles, namely sleptons and winos, in Pb+Pb collisions. At LHC energy Eion=3.5 TeV/u and for rest masses of around m=50 GeV they obtain sigma (w+w-) sigma ((W+, w-)) approximately=10 nb and sigma (l+, l-) approximately=1 nb. Basic features of an impact parameter-dependent treatment of the production mechanism are discussed.}, Doi = {10.1088/0954-3899/16/2/010}, Key = {Rau:1990fv} } @article{Geiger:1990fy, Author = {Geiger, K and uuml, M and ller, B and Greiner, W}, Title = {(eta - eta-prime - iota) mixing, decay and production mechanisms}, Journal = {Z. Phys. C}, Volume = {48}, Pages = {257-272}, Year = {1990}, Key = {Geiger:1990fy} } @article{Ionescu:1990qt, Author = {Lonescu, DC and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Localized bound states of fermions interacting via massive vector bosons}, Journal = {Journal of Mathematical Physics}, Volume = {31}, Number = {3}, Pages = {763-770}, Year = {1990}, ISSN = {0022-2488}, Abstract = {A model for composite systems consisting of fermions with internal degrees of freedom interacting via intermediate vector bosons (IVB) is constructed. Highly localized, low-mass bound states are found in the Hartree-Fock approximation. The dependence of these states as function of the coupling constant and vector boson mass is investigated. In the limit of infinite vector boson mass the interaction is described by Fermi-type contact forces. © 1990 American Institute of Physics.}, Key = {Ionescu:1990qt} } @article{Harley:1990wp, Author = {Harley, D and uuml, M and ller, B and Rafelski, J}, Title = {Muon catalyzed fusion for nuclei with Z > 1}, Journal = {J. Phys. G}, Volume = {16}, Pages = {281-294}, Year = {1990}, Key = {Harley:1990wp} } @article{art107, Author = {Harley, D and Müller, B and Rafelski, J}, Title = {Time independent description of the t(d, n)α fusion reaction in the presence of a muon}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {336}, Number = {3}, Pages = {303-312}, Year = {1990}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01292861}, Abstract = {We describe the (α n μ)-(d t μ) continuum above and below the d+(t μ)1s threshold using the R-matrix formalism. The continuum is explicitly constructed in an adiabatic approximation, and the asymptotic phase shifts and amplitudes in all channels are obtained. The energy eigenstates are used to compute the fusion reaction cross section for in-flight d+(t μ) fusion, and fusion reaction rates involving transitions from the d+(t μ)1s continuum to be below threshold continuum states. © 1990 Springer-Verlag.}, Doi = {10.1007/BF01292861}, Key = {art107} } @article{art106, Author = {Rafelski, HE and Müller, B}, Title = {PC-fortran programs for muon reactivation calculations in muon-cataluzed fusion}, Journal = {Computer Physics Communications}, Volume = {59}, Number = {3}, Pages = {521-526}, Year = {1990}, ISSN = {0010-4655}, Abstract = {The introduction of a μ- particle into a mixture of hydrogen isotopes brings about a repetitive cycle of processes leading to nuclear fusion and the release of energy. Sticking is one of the critical processes limiting the number of fusions induced by one muon during its lifetime. When the (αμ)+ ion created with the energy E=3.46 MeV is slowed down in a dense DT mixture, the muon can be stripped (reactivated), thus allowing the muon to return to the catalytic cycle. The coupled differential equations describing the reaction process are solved using the computer code as documented by L.F. Shampine and M.K. Gordon [Computer Solution of Ordinary Differential Equations, the initial value problem (Freeman, San Francisco, 1975)]. © 1990.}, Key = {art106} } @article{Muller:1990wc, Author = {uuml, M and ller, B and Schramm, AJ}, Title = {Higgs boson production to peripheral heavy ion collisions. 1. Electromagnetic production}, Journal = {Phys. Rev.}, Volume = {D42}, Pages = {3699-3704}, Year = {1990}, Key = {Muller:1990wc} } @article{Augustin:1990hc, Author = {Augustin, J and uuml, M and ller, B and Greiner, W}, Title = {Magnetic neutrino scattering by crystals}, Journal = {Phys. Rev.}, Volume = {D41}, Pages = {1683-1686}, Year = {1990}, Key = {Augustin:1990hc} } @article{Sailer:1990ia, Author = {Sailer, K and Schönfeld, T and Schäfer, A and Müller, B and Greiner, W}, Title = {Transverse size effects in the fragmentation of hadronic strings}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {240}, Number = {3-4}, Pages = {381-388}, Year = {1990}, Abstract = {The transverse momentum distribution of (anti)quarks created in the chromo-electric field of an infinitely long hadronic flux tube is derived. The effects of the finite radius of the hadronic strings on their fragmentation are studied simulating e+e- annihilation events in the framework of a dynamical string model that contains two parameters: the string tension κ=0.89 GeV/fm (determined by the Regge slope), and the radius of the string. It is shown that a string radius of about 0.5 fm allows to describe successfully both the width of the transverse momentum distribution in the low-pT region and the multiplicities.}, Key = {Sailer:1990ia} } @article{Sailer:1990wa, Author = {Sailer, K and Greiner, W and uuml, M and ller, B}, Title = {Hadronic matter in the string model}, Journal = {Adv. Ser. Direct. High Energy Phys.}, Volume = {6}, Pages = {299-392}, Year = {1990}, Key = {Sailer:1990wa} } @article{Schram:1990ej, Author = {Schram, Z and Sailer, K and Müller, B and Greiner, W}, Title = {Boson interferometry in string fragmentation}, Journal = {Zeitschrift für Physik C-Particles and Fields}, Volume = {47}, Number = {1}, Pages = {137-139}, Year = {1990}, ISSN = {0170-9739}, url = {http://dx.doi.org/10.1007/BF01551924}, Abstract = {Bose-Einstein correlation of identical pions in e+e- annihilation at {Mathematical expression} GeV c.m. energy is studied within the framework of a dynamic string model of hadrons. It is shown that taking Fourier transform of the measured correlation function is not a totally satisfactory method to get information on the size of the pion source. © 1990 Springer-Verlag.}, Doi = {10.1007/BF01551924}, Key = {Schram:1990ej} } @article{Augustin:1990rt, Author = {Augustin, J and Graf, S and Müller, B and Greiner, W}, Title = {Production of hypothetical, light neutral particles in high-energy channeling}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {336}, Number = {3}, Pages = {353-356}, Year = {1990}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01292868}, Abstract = {The rates for X° creation by photons and electrons channeling along a crystal axis are estimated. The process is found to depend strongly on the parameters of the crystal fields. Promising X° production rates can therefore be obtained for germanium rather than for lighter elements. © 1990 Springer-Verlag.}, Doi = {10.1007/BF01292868}, Key = {Augustin:1990rt} } @article{Schenfeld:1990yu, Author = {Schönfeld, T and Schäfer, A and Müller, B and Sailer, K and Reinhardt, J and Greiner, W}, Title = {Pair creation in a flux tube}, Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}, Volume = {247}, Number = {1}, Pages = {5-12}, Year = {1990}, Abstract = {We have studied the pair creation rate in a cylindrical region of space with a homogeneous electric field parallel to the cylinder axis. MIT boundary conditions on the surface of the cylinder are imposed. The wave functions of the created particles are calculated. In the limit of the cylinder radius tending towards infinity, the Schwinger formula is reproduced. Finally, the fraction of produced strange particles is studied as a function of the cylinder radius.}, Key = {Schenfeld:1990yu} } @article{Biro:1990vj, Author = {Biro, TS and Levai, P and uuml, M and ller, B}, Title = {Strangeness production with 'massive' gluons}, Journal = {Phys. Rev.}, Volume = {D42}, Pages = {3078-3087}, Year = {1990}, Key = {Biro:1990vj} } @article{fds322937, Author = {Griepenkerl, K and Müller, B and Greiner, W}, Title = {Electron density waves in superconducting matter}, Journal = {Radiation Effects & Defects in Solids}, Volume = {110}, Number = {1-2}, Pages = {215-216}, Year = {1989}, Month = {October}, url = {http://dx.doi.org/10.1080/10420158908214201}, Doi = {10.1080/10420158908214201}, Key = {fds322937} } @article{Sailer:1989eh, Author = {Sailer, K. and Müller, B. and Greiner, W.}, Title = {Numerical simulation of the equation of state for the hadronic matter within the string model}, Journal = {Int. J. Mod. Phys. A}, Volume = {A}, Pages = {437}, Year = {1989}, Key = {Sailer:1989eh} } @article{art100, Author = {deReus, T and uuml, M and ller Nehler, U and Soff, G and Reinhardt, J and uuml, M and ller, B and Greiner, W}, Title = {Coupled-channel results for atomic excitations in intermediate energy heavy ion collisions}, Journal = {Phys. Rev. C}, Volume = {40}, Pages = {752-761}, Year = {1989}, Key = {art100} } @article{art99, Author = {Ionescu, DC and Reinhardt, J and uuml, M and ller, B and Greiner, W and Soff, G}, Title = {Reply to `Comment on Nonlinear interactions and poly-positronium bound states'}, Journal = {J. Phys. G}, Volume = {15}, Pages = {931-932}, Year = {1989}, Key = {art99} } @article{art98, Author = {Ionescu, DC and uuml, M and ller, B and Greiner, W}, Title = {Strongly bound bipositronium states in QED?}, Journal = {J. Phys. G}, Volume = {15}, Pages = {L103-L108}, Year = {1989}, Key = {art98} } @article{art102, Author = {Augustin, J and Müller, B and Greiner, W}, Title = {Spin exchange in low energy electron-ion collisions}, Journal = {Zeitschrift für Physik D-Atoms Molecules and Clusters}, Volume = {14}, Number = {4}, Pages = {317-326}, Year = {1989}, ISSN = {0178-7683}, url = {http://dx.doi.org/10.1007/BF01429281}, Abstract = {The elastic scattering of an electron by a hydrogenic ion of charge (Z-1) is investigated. For scattering energies Ekin in the eV region, where the Bohr-Sommerfeld parameter y is large compared to one, the cross section for spin exchange of the electrons is found to be proportional to Z-2 and E-1kin. Spin exchange is dominated by radiative electron capture for Z>25. © 1989 Springer-Verlag.}, Doi = {10.1007/BF01429281}, Key = {art102} } @article{Neubauer:1989wr, Author = {Neubauer, DSKM and uuml, and ller, BS and ouml, and cker, H and Greiner, W}, Title = {Survival of J/Psi in hadronic matter at high energy density}, Journal = {Mod. Phys. Lett. A}, Volume = {4}, Pages = {1627-1634}, Year = {1989}, Key = {Neubauer:1989wr} } @article{Greiner:1989ig, Author = {Greiner, C and Müller, B}, Title = {Pair correlations of neutral strange particles emitted in relativistic heavy ion collisions}, Journal = {Physics Letters B}, Volume = {219}, Number = {2-3}, Pages = {199-204}, Year = {1989}, ISSN = {0370-2693}, Abstract = {We point out the possible role of neutral strange particles (Λ, KoS) as probes for the size of a baryon-rich fireball formed in relativistic nuclear collisions. A striking difference in the size parameters determined by the hyperons on one hand, and kaons or pions on the other hand, may occur in the case of a phase transition to a quark-gluon plasma. © 1989.}, Key = {Greiner:1989ig} } @article{art105, Author = {Sailer, K and uuml, M and ller, B and Greiner, W}, Title = {Numerical simulation of the equation of state for hadronic matter within the string model}, Journal = {Int. J. Mod. Phys. A}, Volume = {4}, Pages = {437-449}, Year = {1989}, Key = {art105} } @article{Graf:1989vw, Author = {Graf, S and Schramm, S and Reinhardt, J and Muller, B and Greiner, W}, Title = {Composite particle decay as a possible source of e^{+}e^{-}lines in heavy-ion collisions}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {15}, Number = {9}, Pages = {1467-1494}, Year = {1989}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/15/9/017}, Abstract = {The authors discuss an extended particle structure whose decay into e +e- may be the source of the correlated electron-positron coincidences in heavy-ion collisions measured at GSI. The general properties of the particle, like its excitation spectrum and lifetime, are calculated. The production of the particle in heavy-ion collisions and its influence on other experiments is studied.}, Doi = {10.1088/0954-3899/15/9/017}, Key = {Graf:1989vw} } @article{Rafelski:1989wq, Author = {Rafelski, HE and Müller, B and Rafelski, J and Trautmann, D and Viollier, RD}, Title = {Muon reactivation in muon-catalyzed D-T fusion}, Journal = {Progress in Particle and Nuclear Physics}, Volume = {22}, Number = {C}, Pages = {279-338}, Year = {1989}, ISSN = {0146-6410}, Abstract = {We comprehensively reanalyze and search for the density dependence of the effective muon alpha sticking fraction ωsff observed experimentally in muon catalyzed deuterium-tritium fusion. In our work particular emphasis has been put on the density dependent dense hydrogen stopping power. The main technical details and improvements in this work are: The (αμ)+ 2s and 2p states are treated independently and are assigned individual reaction rates. The essential muonic excitation rates have been recalculated taking into account finite nuclear mass effects. The stopping power for a charged projectile in liquid heavy hydrogen is modified to account for dynamic screening effects and a density dependent effective ionization potential. It is shown that the medium dependent stopping power for the (αμ)+ ion is the crucial factor controlling the density dependence of the effective sticking fraction. It is also pointed out that the muonic helium Kα X-ray yield and the sticking fraction at high density can not be simultaneously brought into agreement with the experimental results without invoking novel mechanisms suppressing Stark mixing in the (Heμ) L-shell. © 1989.}, Key = {Rafelski:1989wq} } @article{Grabiak:1989uf, Author = {Grabiak, M and Muller, B and Greiner, W and Soff, G and Koch, P}, Title = {Electroweak physics at ultrarelativistic heavy-ion colliders}, Journal = {Journal of Physics G: Nuclear and Particle Physics}, Volume = {15}, Number = {3}, Pages = {L25-L30}, Year = {1989}, ISSN = {0954-3899}, url = {http://dx.doi.org/10.1088/0954-3899/15/3/001}, Abstract = {Nuclear beams with energies of several TeV per nucleon are considered as carriers of intense fields of photons in the energy range up to 100 GeV. Cross sections for intermediate boson and Higgs production by two-photon collisions are predicted to be in the nanobarn range. Production of heavy neutral particles in peripheral collision could be easily detectable because of low background.}, Doi = {10.1088/0954-3899/15/3/001}, Key = {Grabiak:1989uf} } @article{art104, Author = {uuml, M and ller, B and Rafelski, HE and Rafelski, J}, Title = {Muon spectrum and convoy effects after muon catalyzed fusion}, Journal = {Phys. Rev. A}, Volume = {40}, Pages = {2839-2842}, Year = {1989}, Key = {art104} } @article{art103, Author = {Sch, and auml, and fer, ASGIPM and uuml, and ller, B and Greiner, W}, Title = {Atomic parity violation in U(90+)$}, Journal = {Phys. Rev. A}, Volume = {40}, Number = {12}, Pages = {7362-7365}, Year = {1989}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.40.7362}, Abstract = {Parity mixing of electron states should be extremely strong for heliumlike uranium. We calculate its size and discuss whether it could be determined experimentally. We analyze one specific scheme for such an experiment. The required laser intensities for two-photon spectroscopy of the 23P0-2 1S0level splitting is of the order of 1017 W/cm2. A determination of parity mixing would require at least 1021 W/cm2. Â© 1989 The American Physical Society.}, Doi = {10.1103/PhysRevA.40.7362}, Key = {art103} } @article{art101, Author = {Plunien, G and Müller, B and Greiner, W and Soff, G}, Title = {Nuclear polarization contribution to the Lamb shift in heavy atoms}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {39}, Number = {10}, Pages = {5428-5431}, Year = {1989}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.39.5428}, Abstract = {The energy shift of the 1s1/2 state in U92238 due to virtual excitation of nuclear rotational modes is shown to be a considerable correction for atomic high-precision experiments. In contrast to this, nuclear polarization effects are of minor importance for Lamb-shift studies in Pb82208. © 1989 The American Physical Society.}, Doi = {10.1103/PhysRevA.39.5428}, Key = {art101} } @article{fds304604, Author = {Schäfer, A and Soff, G and Indelicato, P and Müller, B and Greiner, W}, Title = {Prospects for an atomic parity-violation experiment in U90+}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {40}, Number = {12}, Pages = {7362-7365}, Year = {1989}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.40.7362}, Abstract = {Parity mixing of electron states should be extremely strong for heliumlike uranium. We calculate its size and discuss whether it could be determined experimentally. We analyze one specific scheme for such an experiment. The required laser intensities for two-photon spectroscopy of the 23P0-2 1S0level splitting is of the order of 1017 W/cm2. A determination of parity mixing would require at least 1021 W/cm2. © 1989 The American Physical Society.}, Doi = {10.1103/PhysRevA.40.7362}, Key = {fds304604} } @article{fds247266, Author = {Greiner, C and Rischke, D and Rufa, M and Müller, B and Stöcker, H and Maruhn, J and Greiner, W and Koch, P and G-Reinhard, P}, Title = {Strangeness and heavy ion reactions}, Journal = {Nuclear Physics A}, Volume = {479}, Number = {C}, Pages = {295-309}, Year = {1988}, ISSN = {0375-9474}, url = {http://dx.doi.org/10.1016/0375-9474(88)90445-9}, Abstract = {We investigate possible consequences of strangeness formation in heavy ion reactions at different excitation energies. First of all we study ground state properties of multi-Λ hypernuclei. They seem to have strongly enhanced interaction radii and could be observed and produced in secondary non charge changing reactions of high energy heavy ions. At higher energies we present nonequilibrium calculations for hadronisation and evolution of strange particles and discuss their usefulness for quark matter diagnostics. Furthermore, we discuss the possibility of multistrange quark droplet formation during the phase transition from quark to hadron matter. © 1988.}, Doi = {10.1016/0375-9474(88)90445-9}, Key = {fds247266} } @article{art97, Author = {Graf, S and Reinhardt, J and Müller, U and Müller, B and Greiner, W and Reus, TD and Soff, G}, Title = {Electronic excitations in heavy ion collisions with sequential fission}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {329}, Number = {3}, Pages = {365-369}, Year = {1988}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01290242}, Abstract = {We calculate δ-electron and positron distributions resulting from heavy ion collisions under consideration of a sequential fission in the outgoing channel. The resulting spectra are found to be only weakly sensitive to the underlying dynamics of the fission process. Thus experiments of deep inelastic scattering provide information mainly on the primary reaction process. © 1988 Springer-Verlag.}, Doi = {10.1007/BF01290242}, Key = {art97} } @article{art96, Author = {uuml, M and ller, U and deReus, T and Reinhardt, J and uuml, M and ller, B and Greiner, W and Soff, G}, Title = {Positron production in crossed beams of bare uranium nuclei}, Journal = {Phys. Rev. A}, Volume = {37}, Number = {5}, Pages = {1149-1455}, Year = {1988}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.37.1449}, Abstract = {Positron creation in crossed-beam collisions of high-energy, fully stripped heavy ions is investigated within the coupled-channel formalism. In comparison with fixed-target collisions of highly stripped heavy-ion projectiles positron production probabilities are enhanced by more than one order of magnitude. The increase results from the possibility to excite electrons from the negative energy continuum into all bound states. The positron spectrum is shifted towards higher energies because of the absence of electron screening. Rutherford scattering as well as nuclear collisions with time delay are investigated. We also discuss the filling of empty bound states by electrons from pair-production processes. Â© 1988 The American Physical Society.}, Doi = {10.1103/PhysRevA.37.1449}, Key = {art96} } @article{art95, Author = {Graf, O and Reinhardt, J and uuml, M and ller, B and Greiner, W and Soff, G}, Title = {Angular correlations of coincident electron-positron pairs produced in heavy ion collisions with nuclear time delay}, Journal = {Phys. Rev. Lett.}, Volume = {61}, Pages = {2831-2834}, Year = {1988}, Key = {art95} } @article{art94, Author = {Reus, TD and Müller-Nchler, U and Soff, G and Graf, O and Müller, B and Greiner, W}, Title = {Can multiple structures in positron spectra be caused by atomic effects?}, Journal = {Zeitschrift für Physik D-Atoms Molecules and Clusters}, Volume = {8}, Number = {4}, Pages = {305-313}, Year = {1988}, ISSN = {0178-7683}, url = {http://dx.doi.org/10.1007/BF01437096}, Abstract = {In recent experiments at least two structures have been detected in positron spectra from subcritical (total charge Z ≦ 174) heavy-ion collisions at bombarding energies ELab=5.7-5.9 MeV/n. The origin of these structures is unexplained up to now. Atomic effects have already been discussed as a possible source in a previous paper, where a schematic ansatz for the electronic transition matrix elements was employed. Meanwhile numerical calculations for K-vacancy formation also exhibited oscillations in the impact parameter dependence when using this ansatz. In this paper we report on a scaling law describing these oscillations. As a consequence certain subsidiary conditions have to be imposed on our schematic ansatz, which in turn yield a new understanding on eligible atomic sources for multiple structures in the emission spectra of positrons. © 1988 Springer-Verlag.}, Doi = {10.1007/BF01437096}, Key = {art94} } @article{art93, Author = {Ionescu, DC and Reinhardt, J and uuml, M and ller, B and Greiner, W and Soff, G}, Title = {Nonlinear extensions of the Dirac equation and their implications in quantum electrodynamics}, Journal = {Phys. Rev. A}, Volume = {38}, Number = {2}, Pages = {616-620}, Year = {1988}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.38.616}, Abstract = {We investigate the influence of additional nonlinear terms in the Dirac Lagrangian on strongly bound electron states in heavy and superheavy atoms. Upper bounds for the coupling constants are deduced by comparison with precision spectroscopy data in QED. We demonstrate that nonlinear interactions may cause significant modifications of electron binding energies in superheavy quasiatomic systems which would not be visible in ordinary atomic-physics measurements. Â© 1988 The American Physical Society.}, Doi = {10.1103/PhysRevA.38.616}, Key = {art93} } @article{Schaefer:1988pq, Author = {Sch, and auml, and fer, AM and uuml, and ller, B and Greiner, W}, Title = {Local vacuum excitations in strong electromagnetic fields?}, Journal = {Int. J. Mod. Phys. A}, Volume = {3}, Pages = {1751-1757}, Year = {1988}, Key = {Schaefer:1988pq} } @article{Koch:1988nn, Author = {Koch, PM and uuml, and ller, BS and ouml, and cker, H and Greiner, W}, Title = {Antibaryon-baryon ratios as a signal for quark gluon plasma formation}, Journal = {Mod. Phys. Lett. A}, Volume = {3}, Pages = {737-742}, Year = {1988}, Key = {Koch:1988nn} } @article{Schramm:1988np, Author = {Schramm, S and uuml, M and ller, B and Reinhardt, J and Greiner, W}, Title = {Decay of a composite particle as a hypothetical explanation of e+ e- coincidences observed at GSI}, Journal = {Mod. Phys. Lett. A}, Volume = {3}, Pages = {783-793}, Year = {1988}, Key = {Schramm:1988np} } @article{Paulus:1988rn, Author = {Paulus, AFM and uuml, M and ller, B and Greiner, W and Vasak, D}, Title = {Fission of heavy quarkonia in the deformed MIT-bag model}, Journal = {J. Phys. G}, Volume = {14}, Pages = {269-285}, Year = {1988}, Key = {Paulus:1988rn} } @article{Ionescu:1988vq, Author = {Ionescu, DC and Reinhardt, J and Muller, B and Greiner, W and Soff, G}, Title = {Nonlinear interactions and poly-positronium bound states}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {14}, Number = {6}, Pages = {L143-L152}, Year = {1988}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/14/6/004}, Abstract = {The creation of a hypothetical many-electron-positron bound system was suggested as a possible source of the correlated peaks observed in the e + and e- spectra of various heavy-ion collisions. A new electron-electron interaction was assumed, which becomes large in high-Z nuclear collisions. The authors investigate energy states of such (e+e -)n clusters, bound by scalar and vector Fermi-type interactions. For the bi-positronium system (e+e-) 2 they derive a single-particle equation employing the Hartree-Fock method. The required values of the coupling constants are found to be inconsistent with precision QED experiments.}, Doi = {10.1088/0305-4616/14/6/004}, Key = {Ionescu:1988vq} } @article{Kim:1988kv, Author = {Kim, SK and uuml, M and ller, B and Greiner, W}, Title = {Bethe-Salpeter equation for a four fermion system}, Journal = {Mod. Phys. Lett. A}, Volume = {3}, Pages = {953-963}, Year = {1988}, Key = {Kim:1988kv} } @article{Grabiak:1988yh, Author = {Grabiak, M and Müller, B and Greiner, W}, Title = {Exclusion of quasi-bound e^{+}e^{-}states at MeV energies within the framework of QED}, Journal = {Annals of Physics}, Volume = {185}, Number = {2}, Pages = {284-300}, Year = {1988}, ISSN = {0003-4916}, Abstract = {We give general arguments that no narrow quasi-bound e+ e- state can exist above 2me. We extend the virial theorem of QED to quasi-bound states and show that corrections due to renormalization and due to the fact that a resonance is not an energy eigenstate are small. A "magnetically bound" e+ e- state with energy above 2me would violate this extended virial theorem. © 1988.}, Key = {Grabiak:1988yh} } @article{Geiger:1988bt, Author = {Geiger, K and Reinhardt, J and uuml, M and ller, B and Greiner, W}, Title = {Magnetic moment interactions in the e$^{-}$-e$^{+}$ system}, Journal = {Z. Phys. A}, Volume = {329}, Number = {1}, Pages = {77-88}, Year = {1988}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01294818}, Abstract = {We have studied the possible existence of quasibound states of an electron-positron pair due to their magnetic interaction in the framework of the equations suggested by Barut et al. [5]. We derive radial equations for all angular quantum numbers of the e--e+ system and show, in detail, that Barut's equations doe not give a consistent, physically satisfactory description of positronium, except in the non-relativistic approximation (up to terms of order m Î±2). Moreover, we do not find evidence that the effective potentials occurring in the radial equations support magnetic resonances of the e--e+ system at short particle distances ("micropositronium"). Â© 1988 Springer-Verlag.}, Doi = {10.1007/BF01294818}, Key = {Geiger:1988bt} } @article{Heuer:1988st, Author = {Heuer, R and Müller, B and Stöcker, H and Greiner, W}, Title = {Coherent photon production in heavy-ion collisions at intermediate energies}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {330}, Number = {3}, Pages = {315-318}, Year = {1988}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01294876}, Abstract = {We have studied photon production in heavy-ion collisions at intermediate energies in the Molecular Dynamics approach, where the radiation amplitudes have been derived from the many-body dynamics in the classical bremsstrahlung formalism. This concept allows for a comparison of cross sections obtained by coherent and incoherent summation of amplitudes. The numerical results show a significant enhancement of the coherent cross section for photon energies below 40 MeV due to the dynamical influence of the nuclear mean field. © 1988 Springer-Verlag.}, Doi = {10.1007/BF01294876}, Key = {Heuer:1988st} } @article{fds304601, Author = {Ionescu, DC and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Nonlinear extensions of the Dirac equation and their implications in QED}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {38}, Number = {2}, Pages = {616-620}, Year = {1988}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.38.616}, Abstract = {We investigate the influence of additional nonlinear terms in the Dirac Lagrangian on strongly bound electron states in heavy and superheavy atoms. Upper bounds for the coupling constants are deduced by comparison with precision spectroscopy data in QED. We demonstrate that nonlinear interactions may cause significant modifications of electron binding energies in superheavy quasiatomic systems which would not be visible in ordinary atomic-physics measurements. © 1988 The American Physical Society.}, Doi = {10.1103/PhysRevA.38.616}, Key = {fds304601} } @article{fds304602, Author = {Müller, U and Reus, TD and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Positron production in crossed beams of bare uranium nuclei}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {37}, Number = {5}, Pages = {1449-1455}, Year = {1988}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.37.1449}, Abstract = {Positron creation in crossed-beam collisions of high-energy, fully stripped heavy ions is investigated within the coupled-channel formalism. In comparison with fixed-target collisions of highly stripped heavy-ion projectiles positron production probabilities are enhanced by more than one order of magnitude. The increase results from the possibility to excite electrons from the negative energy continuum into all bound states. The positron spectrum is shifted towards higher energies because of the absence of electron screening. Rutherford scattering as well as nuclear collisions with time delay are investigated. We also discuss the filling of empty bound states by electrons from pair-production processes. © 1988 The American Physical Society.}, Doi = {10.1103/PhysRevA.37.1449}, Key = {fds304602} } @article{fds304603, Author = {Geiger, K and Reinhardt, J and Müller, B and Greiner, W}, Title = {Magnetic moment interactions in the e^{-}-e^{+}system}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {329}, Number = {1}, Pages = {77-88}, Year = {1988}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01294818}, Abstract = {We have studied the possible existence of quasibound states of an electron-positron pair due to their magnetic interaction in the framework of the equations suggested by Barut et al. [5]. We derive radial equations for all angular quantum numbers of the e--e+ system and show, in detail, that Barut's equations doe not give a consistent, physically satisfactory description of positronium, except in the non-relativistic approximation (up to terms of order m α2). Moreover, we do not find evidence that the effective potentials occurring in the radial equations support magnetic resonances of the e--e+ system at short particle distances ("micropositronium"). © 1988 Springer-Verlag.}, Doi = {10.1007/BF01294818}, Key = {fds304603} } @article{fds322938, Author = {Soff, G and Schlüter, P and Reinhardt, J and Reus, TD and Wietschorke, K-H and Schäfer, A and Graf, S and Müller, U and Müller, B and Greiner, W}, Title = {Puzzling positron peaks in heavy-ion collisions}, Journal = {Physica Scripta: an international journal for experimental and theoretical physics}, Volume = {36}, Number = {5}, Pages = {743-755}, Year = {1987}, Month = {November}, url = {http://dx.doi.org/10.1088/0031-8949/36/5/002}, Doi = {10.1088/0031-8949/36/5/002}, Key = {fds322938} } @article{fds247209, Author = {Müller, B}, Title = {Strange particles as signature of the quark-gluon plasma: A status report}, Journal = {Nuclear Physics A}, Volume = {461}, Number = {1-2}, Pages = {213-224}, Year = {1987}, ISSN = {0375-9474}, Abstract = {The prospects of detecting the formation of a quark-gluon plasma in nuclear collisions at very high energy are reviewed. Predictions that the strange versus nonstrange antibaryon ratio is a good signal in the baryon-"rich" region are confirmed. The usefulness of this ratio in the baryon-free region depends on the length of the coexistence time of quark-gluon plasma and hadronic matter. © 1987.}, Key = {fds247209} } @article{art92, Author = {Schramm, S and Müller, B and Greiner, W}, Title = {Description of multi-particle cluster correlations in the ground state of many-body systems}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {13}, Number = {5}, Pages = {L69-L73}, Year = {1987}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/13/5/003}, Abstract = {A new method to describe the presence of multi-particle clusters in the ground state (vacuum) of a many-body system is presented. It relies on a unitary transformation in Fock space and can be used to investigate alpha -clustering in nuclei as well as clustering in the QCD and in the QED vacua.}, Doi = {10.1088/0305-4616/13/5/003}, Key = {art92} } @article{art91, Author = {Heinz, H and Müller, B and Greiner, W}, Title = {The relativistic fermi gas in a nonuniform velocity field}, Journal = {Physica A: Statistical Mechanics and its Applications}, Volume = {140}, Number = {3}, Pages = {567-584}, Year = {1987}, ISSN = {0378-4371}, Abstract = {We review the relativistic Fermi gas in an inhomogeneous velocity field and calculate components of the current vector and the energy-momentum tensor in a comoving frame. We derive quantum corrections to the classical distribution function in the framework of the grand canonical ensemble. © 1987.}, Key = {art91} } @article{art90, Author = {Danos, M and uuml, M and ller, B and Rafelski, J}, Title = {Comment on `Muon alpha-particle sticking probability in muon catalyzed fusion'}, Journal = {Phys. Rev. A}, Volume = {35}, Pages = {2741-2743}, Year = {1987}, Key = {art90} } @article{art89, Author = {Müller, B and Takigawa, N}, Title = {How adiabatic is quantum tunneling?}, Journal = {Annals of Physics}, Volume = {173}, Number = {1}, Pages = {163-184}, Year = {1987}, ISSN = {0003-4916}, Abstract = {We consider the coupling between collective and intrinsic degrees of freedom of a many-dimensional quantum system. We give a criterion for the validity of the adiabatic approximation in tunneling processes and derive an equation for the "lag" of the intrinsic wave function with respect to the adiabatic groundstate. Solutions for several simple cases are presented. © 1987.}, Key = {art89} } @article{art88, Author = {Graf, O and Reinhardt, J and Reus, TD and Müller, B and Greiner, W and Soff, G}, Title = {Angular correlations of electron-positron pairs produced in heavy-ion collisions}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {328}, Number = {1}, Pages = {81-84}, Year = {1987}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01295185}, Abstract = {We investigate the strength of angular correlations between coincident electron-positron pairs produced in Pb + Pb collisions at 5.7 MeV/u. The angular correlations are predicted to be observable at electron energies above 200 keV, almost independent of positron energy. © 1987 Springer-Verlag.}, Doi = {10.1007/BF01295185}, Key = {art88} } @article{art87, Author = {Mehler, G and uuml, M and ller, B and Greiner, W and Soff, G}, Title = {K-shell ionization by antiprotons}, Journal = {Phys. Rev. A}, Volume = {36}, Pages = {1454-1457}, Year = {1987}, Key = {art87} } @article{art86, Author = {Mehler, G and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Calculation of L_{3}subshell alignment within a coupled-state formalism}, Journal = {Zeitschrift für Physik D-Atoms Molecules and Clusters}, Volume = {5}, Number = {2}, Pages = {143-145}, Year = {1987}, ISSN = {0178-7683}, url = {http://dx.doi.org/10.1007/BF01436888}, Abstract = {Theoretical results for the impact parameter dependence of the A20 alignment parameter are compared with experimental data. The calculations have been performed within a coupled channel formalism, using relativistic atomic wave functions as basis states. © 1987 Springer-Verlag.}, Doi = {10.1007/BF01436888}, Key = {art86} } @article{art85, Author = {Reus, TD and Reinhardt, J and Müller, U and Müller, B and Greiner, W and Soff, G}, Title = {Positron and delta electron emission in the systems Ta + Th and Au + U}, Journal = {Physica B: Physics of Condensed Matter & C: Atomic, Molecular and Plasma Physics, Optics}, Volume = {144}, Number = {2}, Pages = {237-246}, Year = {1987}, ISSN = {0378-4363}, Abstract = {We present theoretical positron- and δ-electron spectra for the sub-critical systems Ta + Th (Ztot = 163) and U + Au (Ztot = 171) as a function of impact parameter b and laboratory angle θL. For the system Ta + Th in addition the excitation function for dynamical positron emission in the vicinity of the Coulomb barrier was evaluated. Assuming the formation of long-lived giant nuclei, we determine the kinetic energy Te+ at which spontaneous positron emission occurs as a function of Ztot. For constant values of Te+ we evaluated the corresponding nuclear densities in dependence on the total nuclear charge. © 1987.}, Key = {art85} } @article{art84, Author = {Schramm, S and Reinhardt, J and Müller, B and Greiner, W}, Title = {Electron-positron scattering matrix in supercritical heavy-ion collisions}, Journal = {Physics Letters B}, Volume = {198}, Number = {2}, Pages = {136-138}, Year = {1987}, ISSN = {0370-2693}, Abstract = {The scattering matrix describing the electron-positron excitation during a heavy-ion collision is discussed. It is shown that spontaneous positron emission in the presence of a long nuclear delay time precisely corresponds to the formal resonance condition of Scharf. © 1987.}, Key = {art84} } @article{art83, Author = {Reinhardt, J and Scherdin, A and Müller, B and Greiner, W}, Title = {Resonant Bhabha scattering at MeV energies}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {327}, Number = {4}, Pages = {367-381}, Year = {1987}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01289561}, Abstract = {We discuss, on a phenomenological level, the possible appearance of resonances in e++e- scattering at energies in the MeV region. The expected resonance cross section and angular distribution are examined. The observability depends crucially on the attainable energy resolution which is limit by the momentum distribution of the electrons contained in the target. © 1987 Springer-Verlag.}, Doi = {10.1007/BF01289561}, Key = {art83} } @article{Tupper:1987sf, Author = {Tupper, G and Danos, M and Müller, B and Rafelski, J}, Title = {On the detection of cosmic-background neutrinos by acoustic phonon scattering}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {35}, Number = {1}, Pages = {394-396}, Year = {1987}, ISSN = {0556-2821}, url = {http://dx.doi.org/10.1103/PhysRevD.35.394}, Abstract = {We examine the possible detection of cosmic-background neutrinos by coherent neutrino-phonon scattering. Our conclusion is that at least for simple detector schemes the reaction rate is unobservably small. © 1987 The American Physical Society.}, Doi = {10.1103/PhysRevD.35.394}, Key = {Tupper:1987sf} } @article{Grabiak:1987qt, Author = {Grabiak, M and Staadt, G and Müller, B and Greiner, W and Schäfer, A}, Title = {Spontaneously broken gauge theory in strong external fields}, Journal = {Physics Letters B}, Volume = {183}, Number = {3-4}, Pages = {259-262}, Year = {1987}, ISSN = {0370-2693}, Abstract = {It was proposed in a former paper [A. Schäfer, B. Müller and W. Greiner, Phys. Lett. B 149 (1984) 455] that in strong fields the VEV of a Higgs field can become space and time dependent and that the Goldstone boson might become visible. As an example the Glashow-Salam-Weinberg (GSW) in a strong electromagnetic field was discussed. A careful analysis, however, shows that this process is not possible unless the strength of the electric field is of the same order of magnitude as the mass of the heavy vector bosons W and Z which is about 80 GeV. The basic reason for this that a space-dependent Higgs vacuum which is needed in order to screen the electric field physically corresponds to a W-field. Because of the large mass of the W-boson this field cannot be excited unless the strength of the electric field is of the same order of magnitude as the mass of the W-boson. © 1987.}, Key = {Grabiak:1987qt} } @article{Schaefer:1987sk, Author = {Sch, and auml, and fer, AM and uuml, and ller, B and Reinhardt, J}, Title = {Consequences of a hypothetical light vector boson in nuclear decays}, Journal = {Mod. Phys. Lett. A}, Volume = {2}, Pages = {159-162}, Year = {1987}, Key = {Schaefer:1987sk} } @article{Plunien:1987fr, Author = {Plunien, G and Müller, B and Greiner, W}, Title = {Casimir energy at finite temperature}, Journal = {Physica A: Statistical Mechanics and its Applications}, Volume = {145}, Number = {1-2}, Pages = {202-219}, Year = {1987}, ISSN = {0378-4371}, Abstract = {We derive an integral representation for the temperature corrections to the Casimir effect between perfectly conducting parallel plates placed in the electromagnetic field for arbitrary dimension. The representation has the advantage that dependence upon the external constraints and thermal effects enter separately. The so-called mode sum function carrying the dependence on the boundaries is closely connected with the mode number density which is derived explicitly for the parallel plate configuration. The relation to local Green function methods is also pointed out. © 1987.}, Key = {Plunien:1987fr} } @article{Stahl:1987xw, Author = {Stahl, T and Uhlig, M and Müller, B and Greiner, W and Vasak, D}, Title = {Pion and photon bremsstrahlung in a heavy ion reaction model with friction}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {327}, Number = {3}, Pages = {311-322}, Year = {1987}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01284455}, Abstract = {Based on a classical dynamical model of nuclear motion with a velocity dependent friction force we calculate pionic and electromagnetic bremsstrahlung emitted in heavy ion collisions with bombarding energies between 20 and 84 MeV/n. For arbitrary projectile-target combinations and with a fixed value of the only parameter of the model, the friction coefficient κ, our calculations reproduce the observed beam energy and target mass dependence for pions. The gamma yields, calculated with the same value of κ, reproduce the measured dependence of the cross-section on energy and target mass, but underestimate the published data by a factor two. This is a good agreement in view of the discrepancies between different experimental groups. © 1987 Springer-Verlag.}, Doi = {10.1007/BF01284455}, Key = {Stahl:1987xw} } @article{fds247175, Author = {Rafelski, J and Müller, B}, Title = {Strangeness Production in the Quark-Gluon Plasma}, Journal = {Physical Review Letters}, Volume = {56}, Number = {21}, Pages = {2334-2334}, Year = {1986}, Month = {May}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.56.2334}, Doi = {10.1103/PhysRevLett.56.2334}, Key = {fds247175} } @article{fds247265, Author = {Müller, B and Reinhardt, J and Greiner, W and Schäfer, A}, Title = {Erratum: Is there a tightly bound poly-positronium state? (Journal of Physics G: Nuclear Physics (1986) 12 (L109-L112))}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {12}, Number = {5}, Pages = {477-}, Year = {1986}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/12/5/511}, Doi = {10.1088/0305-4616/12/5/511}, Key = {fds247265} } @article{art82, Author = {Sch, and auml, and fer, A and M, and uuml, and ller, B}, Title = {Bounds on the fractal dimension of space}, Journal = {J. Phys. A}, Volume = {19}, Pages = {3891-3902}, Year = {1986}, Key = {art82} } @article{art81, Author = {Danos, M and uuml, M and ller, B and Rafelski, J}, Title = {Detuning reduction of muon sticking in resonant muon-catalyzed d-t fusion}, Journal = {Phys. Rev. A}, Volume = {34}, Pages = {3642-3645}, Year = {1986}, Key = {art81} } @article{art80, Author = {Reus, TD and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {A new scaling law for electron emission in intermediate-energy heavy ion collisions}, Journal = {Physics Letters B}, Volume = {169}, Number = {2-3}, Pages = {139-142}, Year = {1986}, ISSN = {0370-2693}, Abstract = {A new scaling law is presented for the emission of electrons in intermediate-energy heavy ion collisions. An improved formula is obtained which correctly describes electron emission also in the limit of very short nuclear stopping times τ. In this limit the intensity falls off with the fourth power of the kinetic energy Ee - of the emitted electrons. © 1986.}, Key = {art80} } @article{art79, Author = {Kirsch, J and Müller, B and Greiner, W}, Title = {MO-radiation interference phenomena as a "clock" for nuclear reaction times}, Journal = {Zeitschrift für Physik D-Atoms Molecules and Clusters}, Volume = {1}, Number = {1}, Pages = {47-50}, Year = {1986}, ISSN = {0178-7683}, url = {http://dx.doi.org/10.1007/BF01384657}, Abstract = {Molecular orbital K x-rays emitted during Pb+Pb collisions are investigated. Two results are presented: A slight filling up of the minimum observed in the differential radiation cross-section is given by radiative transitions from the M-shell to the L-shell. The minima are shifted with increasing nuclear contact times to higher photon energies. The observation of the shift allows the estimation of the sticking time. © 1986 Springer-Verlag.}, Doi = {10.1007/BF01384657}, Key = {art79} } @article{art78, Author = {Sch, MWEMJDDKSDWSFSDRMBEM and auml, and fer, A and M, and uuml, and ller, B}, Title = {Search for correlated narrow-peak structure in the two-photon spectrum from 6-MeV/nucleon U+Th collisions}, Journal = {Phys. Rev. Lett.}, Volume = {57}, Pages = {2139-2142}, Year = {1986}, Key = {art78} } @article{art77, Author = {Schäfer, A and Reinhardt, J and Müller, B and Greiner, W}, Title = {Models for new particle production in nuclear collisions}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {324}, Number = {3}, Pages = {243-259}, Year = {1986}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01294578}, Abstract = {Following up our earlier work and also stimulated by recent experimental results on positron production in heavy ion collisions we investigate various mechanisms for the production of a light, previously unknown particle in such collisions. As more conventional mechanisms seem to be inadequate we concentrate on processes directly or indirectly connected with the strong electric or magnetic fields and quark degrees of freedom in nuclei. We also consider modifications of the color confinement scheme. Our analysis is confined to schemes staying within the framework of the standard SU(3)c ×SU(2)×U(1) model. Since most of the possibilities discussed can be rejected, severe modifications of basic concepts of particle physics seem to be required if the production of a new particle is confirmed. © 1986 Springer-Verlag.}, Doi = {10.1007/BF01294578}, Key = {art77} } @article{art76, Author = {Müller, U and Reus, TD and Reinhardt, J and Müller, B and Greiner, W}, Title = {Systematics of spontaneous positron lines}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {323}, Number = {3}, Pages = {261-274}, Year = {1986}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01283784}, Abstract = {Dynamical and spontaneous positron emission are investigated for heavy-ion collisions with long time delay using a semiclassical description. Numerical results and analytical expressions for the characteristic quantities of the resulting spontaneous positron line, i.e., its position, width, and cross section, are compared. The expected behaviour of the line position and cross section and its visibility against the spectrum of dynamically created positrons is discussed in dependence on the united charge Zu of projectile and target nucleus in a range of systems from Zu=180 up to Zu=188. The results are confronted with presently available experimental data, and possible implications on further experiments are worked out. © 1986 Springer-Verlag.}, Doi = {10.1007/BF01283784}, Key = {art76} } @article{art75, Author = {Schramm, S and Reinhardt, J and Müller, U and Müller, B and Greiner, W}, Title = {Positron line structures in U-U collisions}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {323}, Number = {3}, Pages = {275-280}, Year = {1986}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01283785}, Abstract = {U-U collisions at energies near the Coulomb barrier are discussed. A quantum mechanical treatment of nuclear motion including the influence of quasibound states in a pocket of the scattering potential is developed. Positron emission probabilities are calculated exhibiting a sharp line due to the decay of a hole in the supercritical 1 s-state. In addition conversion processes and multiple pockets in the potential creating sidebands in the spectrum are computed. © 1986 Springer-Verlag.}, Doi = {10.1007/BF01283785}, Key = {art75} } @article{Rafelski:1986hf, Author = {Koch, P and Müller, B and Rafelski, J}, Title = {Strangeness production and evolution in quark gluon plasma}, Journal = {Zeitschrift fur Physik. A, Atomic nuclei}, Volume = {324}, Number = {4}, Pages = {453-463}, Year = {1986}, ISSN = {0930-1151}, url = {http://dx.doi.org/10.1007/BF01290929}, Abstract = {The formation and evolution of strange quarks in quark gluon plasma is studied assuming perturbative QCD and qualitative models of plasma phase expansion. Chemical equilibrium abundance characteristic of the hottest and densest phase of nuclear collisions is proven to survive the process of expansion and cooling of the plasma. © 1986 Springer-Verlag.}, Doi = {10.1007/BF01290929}, Key = {Rafelski:1986hf} } @article{Muller:1986hy, Author = {Müller, B and Rafelski, J}, Title = {Production of light pseudoscalar particles in heavy-ion collisions}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {34}, Number = {9}, Pages = {2896-2899}, Year = {1986}, ISSN = {0556-2821}, url = {http://dx.doi.org/10.1103/PhysRevD.34.2896}, Abstract = {We calculate the cross section for the production of a hypothetical light neutral pseudoscalar particle in heavy-ion collisions due to the two-photon process. For an inverse coupling strength f in the 100-GeV range we predict a cross section of 10-14 fm2 for production of a particle with 1.5-MeV mass. For the maximal allowed coupling f=5 MeV and an effective reduction of the particle mass due to binding the cross section may reach in to the b range. © 1986 The American Physical Society.}, Doi = {10.1103/PhysRevD.34.2896}, Key = {Muller:1986hy} } @article{Koch:1986ud, Author = {Koch, P and Müller, B and Rafelski, J}, Title = {Strangeness in relativistic heavy ion collisions}, Journal = {Physics Reports}, Volume = {142}, Number = {4}, Pages = {167-262}, Year = {1986}, ISSN = {0370-1573}, Abstract = {Abundances of strange antibaryons formed in nuclear collisions at above 10 GeV/A are considered as a most accessible diagnostic tool for the study of the possible formation and physical properties of the quark-gluon plasma phase of hadronic matter. In this report we describe the current status and develop a dynamical approach in order to describe strange particle formation in nuclear collisions at high energy. © 1986.}, Key = {Koch:1986ud} } @article{Reinhardt:1986rj, Author = {Reinhardt, J and Schäfer, A and Müller, B and Greiner, W}, Title = {Phenomenological consequences of a hypothetical light neutral particle in heavy ion collisions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {33}, Number = {1}, Pages = {194-207}, Year = {1986}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.33.194}, Abstract = {We discuss the possibility that the line structure observed in the spectrum of the positrons produced in heavy ion collisions is due to the decay of a new neutral elementary particle. We argue that this can be ruled out unless one is willing to accept fine tuning of parameters, or to assume the dominance of nonlinear effects. © 1986 The American Physical Society.}, Doi = {10.1103/PhysRevC.33.194}, Key = {Reinhardt:1986rj} } @article{Plunien:1986ca, Author = {Plunien, G and Müller, B and Greiner, W}, Title = {The Casimir effect}, Journal = {Physics Reports}, Volume = {134}, Number = {2-3}, Pages = {87-193}, Year = {1986}, ISSN = {0370-1573}, Abstract = {This report gives an introduction to the Casimir effect in quantum field theory and its applications. The interaction between the vacuum of a quantized field and an external boundary or a classical external field is investigated laying particular emphasis on Casimir's concept of measurable change in the vacuum energy. The various methods for evaluation and regularization of the Casimir energy are discussed in detail for specific field configurations. Recent applications of the Casimir effect in supercritical fields, QCD bag models and electromagnetic media are reviewed. © 1986.}, Key = {Plunien:1986ca} } @article{Muller:1986ch, Author = {Müller, B and Reinhardt, J}, Title = {Comment on "production mechanisms for a new neutral particle below 2 MeV"}, Journal = {Physical Review Letters}, Volume = {56}, Number = {19}, Pages = {2108-}, Year = {1986}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.56.2108}, Doi = {10.1103/PhysRevLett.56.2108}, Key = {Muller:1986ch} } @article{Schafer:1986js, Author = {Sch, and auml, and fer, ARJGW and M, and uuml, and ller, B}, Title = {Elementary light neutral bosons: New limits from precision experiments}, Journal = {Mod. Phys. Lett. A}, Volume = {1}, Pages = {1-7}, Year = {1986}, Key = {Schafer:1986js} } @article{Muller:1986kg, Author = {Müller, B and Reinhardt, J and Greiner, W and Schafer, A}, Title = {Is there a tightly bound poly-positronium state?}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {12}, Number = {4}, Pages = {L109-L112}, Year = {1986}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/12/4/002}, Abstract = {The authors suggest that a system containing several electron-positron pairs (an 'e+e- droplet') could be highly localised and tightly bound if there exists a many-body force of short range acting between leptons. Such a state could have properties required to explain the results of recent electron-positron coincidence experiments at GSI.}, Doi = {10.1088/0305-4616/12/4/002}, Key = {Muller:1986kg} } @article{Grabiak:1986si, Author = {Grabiak, M and Müller, B and Greiner, W}, Title = {Geometrical properties of gauge theories}, Journal = {Annals of Physics}, Volume = {172}, Number = {1}, Pages = {213-242}, Year = {1986}, ISSN = {0003-4916}, Abstract = {We calculate the metric of the orbit space in the free Yang-Mills theory and in scalar electrodynamics. From this metric we derive the curvature of the orbit space. We examine singular points where the curvature is ill defined. Finally we discuss the relation of the metric to the topological properties of the orbit space and the instanton solution. © 1986.}, Key = {Grabiak:1986si} } @article{Muller:1986bt, Author = {M, and uuml, and ller, B and Sch, and auml, and fer, A}, Title = {Improved bounds on the dimension of space-time}, Journal = {Phys. Rev. Lett.}, Volume = {56}, Pages = {1215-1218}, Year = {1986}, Key = {Muller:1986bt} } @article{fds247203, Author = {Reus, TD and Reinhardt, J and Müller, B and Greiner, W and Müller, U and Soff, G}, Title = {Delta electron emission as an atomic clock in deep-inelastic and intermediate energy heavy ion collisions}, Journal = {Progress in Particle and Nuclear Physics}, Volume = {15}, Number = {C}, Pages = {57-75}, Year = {1985}, ISSN = {0146-6410}, Abstract = {We investigate the spectra of electrons which are emitted during heavy ion collisions, traditionally denoted as δ-electrons. The slope in the kinetic energy distribution of ejected δ-electrons provides a finger-print of the occuring delay and deceleration times of the underlying deep-inelastic and intermediate energy collisions on the time scale 10-21 - 10-24s. © 1985.}, Key = {fds247203} } @article{fds247204, Author = {Fink, J and Maruhn, JA and Müller, B and Müller, U and Neise, L and Reinhardt, J and Reus, TD and Schäfer, A and Schlüter, P and Schmidt, W and Schramm, S and Soff, G and Vasak, D and Greiner, W}, Title = {The decay of the vacuum in supercritical fields of giant nuclear systems}, Journal = {Progress in Particle and Nuclear Physics}, Volume = {15}, Number = {C}, Pages = {1-55}, Year = {1985}, ISSN = {0146-6410}, Abstract = {The structure of the vacuum has become of general importance in modern physics. In this context the vacuum of quantum electrodynamics plays a special role because it changes drastically in strong external electric fields and these changes can be followed in a controllable way in the laboratory. It is reviewed how in supercritical electric fields the electron-positron-vacuum, i.e., the ground state of QED is changing from a neutral to a charged vacuum. The theoretical concepts, developed during the last 15 years, can be tested in collisions of very heavy ions, like U+U, U+Cm, etc. The important theoretical and experimental stages are described; in particular it is shown that the vacuum decay might have recently been experimentally verified: Sharp line structures in the positron spectra with pronounced threshold effects are the signals of this fundamental phase transition. Furthermore, the observed γ-ray and δ-electron spectra, the non-appearance of a massive line structure in undercritical systems like U+Ta and the quantitative understanding of the innershell ionization phenomena in giant quasimolecules (their agreement with theoretical predictions) give confidence into this interpretation. At the same time the position line structures possibly indicate the existence of rather long living giant nuclear system with Z ∼ 180-190. It is shown that most likely giant nuclear molecules have been formed as doorway states, but that other new not yet completely understood nuclear structure of giant complexes is indicated. The structure of the giant complexes can eventually be investigated spectroscopically by the positrons from the vacuum: The positron spectrum should not only show the vacuum decay line, but also Raman and Stokes satellites revealing the nuclear collective modes of the giant system formed. Various minima in the collective potential of giant systems should reveal the vacuum decay and their own local nuclear structure through corresponding classes of positron lines. The seemingly constancy with (ZT + ZP) of the principal positron line structure observed so far could indicate the formation of always the same giant object. Other possibilities to explain this effect (vacuum vibrations, excitation of the same nuclear mode in various giant systems and its supercritical conversion) are also discussed. In particular, the possibility of the creation and decay of a yet unknown particle causing constant positron line structure is shown to be in contradiction with atomic precision experiments. Finally the overcritical phenomenon in other areas of physics (e.g., overcritical gluo-electric fields, overcritical gravitational fields) is shortly discussed. © 1985.}, Key = {fds247204} } @article{fds247205, Author = {Müller, B and Ottinger, C and Yang, M}, Title = {L_{α}emission from collisional excitation of H Atoms by threshold energy Ar^{+}ions}, Volume = {320}, Number = {1}, Pages = {61-69}, Year = {1985}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01411926}, Abstract = {In a specially designed collision chamber, H atoms produced by a microwave discharge were excited into the 2 p state by impact of Ar+ ions in a beam. A degree of dissociation up to η=94% was measured at the exit of the microwave source, although in the center of the collision cell η is smaller, with a lower limit of 33 %. The effect of vibrational excitation of H2 by the discharge and the resulting difficulties of measuring η are discussed. The cross section for Lα emission increases linearly from the threshold, at 10.2 eVCM, to 17.1 eVCM. The absolute cross section at this energy is 1.5·10-17 cm2 for η=33% (with a minimum of 0.6·10-17 cm2, for the maximum possible η). The absence of an activation barrier rules out some features shown by an earlier ab initio calculation. © 1985 Springer-Verlag.}, Doi = {10.1007/BF01411926}, Key = {fds247205} } @article{fds247206, Author = {Soff, G and Müller, U and Reus, TD and Reinhardt, J and Müller, B and Greiner, W}, Title = {Atomic excitations in supercritical fields of giant nuclear systems}, Journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, Volume = {10-11}, Number = {PART 1}, Pages = {214-218}, Year = {1985}, ISSN = {0168-583X}, Abstract = {Theoretical results for the δ-electron distribution and positron emission in superheavy systems are compared with recent experimental data. Special emphasis is laid on atomic excitations in deep inelastic nuclear collisions. It is demonstrated that the study of heavy-ion collisions with nuclear time delay promises a clear signature for the spontaneous positron emission. Corresponding experimental results show evidence for this transition from the neutral vacuum to a charged ground state and for the existence of long living nuclear molecules. © 1985.}, Key = {fds247206} } @article{fds247207, Author = {Soff, G and Müller, U and Reus, TD and Reinhardt, J and Müller, B and Greiner, W}, Title = {Superheavy quasi-atoms and quantum electrodynamics in strong fields}, Journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, Volume = {9}, Number = {4}, Pages = {747-752}, Year = {1985}, ISSN = {0168-583X}, Abstract = {Distinct peak structures have been observed in spectra of positrons emitted in collisions of very heavy ions such as U-Th, U-U, Th-Cm and U-Cm. Characteristic features of these structures are discussed and confronted with our theoretical results. It is argued that this experimental finding could be associated with the spontaneous positron emission in the strong Coulomb field of giant nuclear molecules. © 1985.}, Key = {fds247207} } @article{fds247208, Author = {Schäfer, A and Müller, B and Greiner, W}, Title = {Dirakovskiye chastitsy v polye magnitnykh monopolyei i silyanykh Elyektrichyeskikh zaryadov}, Journal = {Il Nuovo Cimento A Series 10}, Volume = {89}, Number = {4}, Pages = {437-451}, Year = {1985}, ISSN = {0369-3546}, url = {http://dx.doi.org/10.1007/BF02884096}, Abstract = {The field of a magnetic pointlike monopole acts in a similar way on a charged Dirac particle as the field of a very strong electric point charge. To explore this parallel we construct a field solution for an extended magnetic-charge distribution. In contrast to what is found for extended electric charges, the Hamiltonian remains non-self-adjoint for an extended magnetic monopole. This suggests that there exists a fundamental difference between the two cases. In particular, the appearance of undefined states for point monopoles is not a consequence of the mere strength of the magnetic-monopole charge, which has a minimum value fixed by Dirac's quantization condition. © 1985 Società Italiana di Fisica.}, Doi = {10.1007/BF02884096}, Key = {fds247208} } @article{art74, Author = {Bosch, F and uuml, M and ller, B}, Title = {Positron production in heavy-ion collisions}, Journal = {Prog. Part. Nucl. Science}, Volume = {16}, Pages = {195-241}, Year = {1985}, Key = {art74} } @article{art72, Author = {Mehler, G and Reus, TD and Müller, U and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Coupled state analysis of electron excitations in asymmetric collision systems}, Journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, Volume = {240}, Number = {3}, Pages = {559-566}, Year = {1985}, ISSN = {0168-9002}, url = {http://dx.doi.org/10.1016/0168-9002(85)90682-5}, Abstract = {A coupled channel formalism is presented, using relativistic basis states of the target atom. Screening effects are incorporated by means of an effective potential of the Hartree-Fock-Slater type. Relativistic wave packets are employed for the description of the continuum. The impact parameter dependence of the K-hole production in p-Ag collisions is calculated, including quadrupole contributions of the projectile Coulomb potential. The results are compared with experimental data. © 1985.}, Doi = {10.1016/0168-9002(85)90682-5}, Key = {art72} } @article{art71, Author = {Reus, TD and Reinhardt, J and Müller, B and Müller, U and Soff, G and Greiner, W}, Title = {Electromagnetic probes of nuclear collisions at intermediate energy}, Volume = {321}, Number = {4}, Pages = {589-592}, Year = {1985}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01432434}, Abstract = {We show that emission of high-energy electrons and photons in nuclear collisions at intermediate energies is sensitive to the space-time evolution of the reaction. The electron and photon spectra measure related but complementary quantities connected with the nuclear charge distribution. We show that at 60 MeV/u beam energy production of 50 MeV electrons is predicted to measurable probability. © 1985 Springer-Verlag.}, Doi = {10.1007/BF01432434}, Key = {art71} } @article{art70, Author = {Reinhardt, J and Müller, B and Greiner, W}, Title = {Comment on "new atomic mechanism for positron production in heavy-ion collisoins"}, Journal = {Physical Review Letters}, Volume = {55}, Number = {1}, Pages = {134-}, Year = {1985}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.55.134}, Abstract = {A Comment on the Letter by W. Lichten and A. Robatino, Phys. Rev. Lett. 54, 781 (1985). © 1985 The American Physical Society.}, Doi = {10.1103/PhysRevLett.55.134}, Key = {art70} } @article{Rafelski:1985pb, Author = {Rafelski, J and Müller, B}, Title = {Muon sticking in muon catalysed doorway D-T fusion}, Journal = {Physics Letters B}, Volume = {164}, Number = {4-6}, Pages = {223-227}, Year = {1985}, ISSN = {0370-2693}, Abstract = {Loss of muons due to capture (sticking) by the α-particle formed in a muon catalysed D-T fusion process driven by the intermediate nuclear resonant state in 5He( 3 2+) is investigated. Depending on the properties of the resonant doorway state, the muon sticking probability can be somewhat greater or significantly smaller than the value ≲1% obtained under the hypothesis that the nuclear D-T interaction is independent of relative momentum. © 1985.}, Key = {Rafelski:1985pb} } @article{Schafer:1985fg, Author = {Sch, and auml, and fer, AM and uuml, and ller, B and Greiner, W}, Title = {Dirac particles in the field of magnetic monopoles and of strong electric charges}, Journal = {Nuovo Cim. A}, Volume = {89}, Pages = {437-451}, Year = {1985}, Key = {Schafer:1985fg} } @article{Schafer:1985eu, Author = {Schäfer, A and Müller, B and Greiner, W}, Title = {Hartree-Fock-calculation of parity-violation in cesium}, Volume = {322}, Number = {4}, Pages = {539-545}, Year = {1985}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01415132}, Abstract = {We present a relativistic Hartree-Fock calculation of the parity violating E1-matrixelement of the 6 s↔7 s transition in cesium. Our result E1= -8.4·10-12iea0 for sin2θw = 0.22 is in good agreement with the experimental value. We also give a general discussion of the consequences of a violation of discrete symmetries for the solutions of the Dirac equation. © 1985 Springer-Verlag.}, Doi = {10.1007/BF01415132}, Key = {Schafer:1985eu} } @article{Vasak:1985dd, Author = {Vasak, D and uuml, M and ller, B and Greiner, W}, Title = {Pion and gamma-ray bremsstrahlung in nuclear collisions at intermediate energies}, Journal = {J. Phys. G}, Volume = {11}, Pages = {1309-1322}, Year = {1985}, Key = {Vasak:1985dd} } @article{Schafer:1985qb, Author = {Schafer, A and Reinhardt, J and Muller, B and Greiner, W and Soff, G}, Title = {Is there evidence for the production of a new particle in heavy-ion collisions?}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {11}, Number = {5}, Pages = {L69-L74}, Year = {1985}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/11/5/001}, Abstract = {The possibility of the production of a new neutral elementary particle in heavy-ion collisions is discussed.}, Doi = {10.1088/0305-4616/11/5/001}, Key = {Schafer:1985qb} } @article{Muller:1985my, Author = {Müller, B and Eisenberg, JM}, Title = {Quark-gluon plasma cooling through pion emission in a chiral bag model}, Journal = {Nuclear Physics A}, Volume = {435}, Number = {3-4}, Pages = {791-809}, Year = {1985}, ISSN = {0375-9474}, Abstract = {A hypothetical quark-gluon plasma is described as a large bag, filled with quarks, antiquarks, and gluons, of radius R ∼ 2-6 fm and temperature T ∼ 100-250 MeV. We consider the cooling of this plasma through pion emission at the bag surface in a chiral-model approach. Comparison is made between results for a large, spherical bag and a model in the limit in which the plasma fills half of space and pion emission is across a planar interface. We find a rather low initial cooling rate per unit surface area for this mechanism, of roughly (10-100) × 1023 MeV/fm2.s. This rate per unit surface becomes independent of R for R ≥ 3 fm, and, because of the nature of the coupling in the chiral bag model, varies with temperature as T6. © 1985.}, Key = {Muller:1985my} } @article{art69, Author = {Vasak, DGWM and uuml, and ller, BST and Uhlig, M}, Title = {Pionic bremsstrahlung in heavy-ion collisions}, Journal = {Nucl. Phys. A}, Volume = {428}, Pages = {291c-304c}, Year = {1984}, Key = {art69} } @article{art68, Author = {Schäfer, A and Müller, B and Vasak, D and Greiner, W}, Title = {Electric and magnetic polarizability of the nucleon in the MIT bag model}, Journal = {Physics Letters B}, Volume = {143}, Number = {4-6}, Pages = {323-325}, Year = {1984}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(84)91474-6}, Abstract = {The electric and magnetic polarizabilities of the proton and neutron are calculated in the framework of the MIT bag model. Neglecting vacuum-polarization we get αp = αn = 10.8 × 10-4 fm3, βp = 2.3 × 10-4 fm3 and βn = 1.5 × 10-4 fm3, in good agreement with experiment. The difficulties in treating the vacuum-polarization consistenly are discussed. It is argued that the polarizabilities may offer a possibility to measure the effective size of nucleon bags inside of nuclei. © 1984.}, Doi = {10.1016/0370-2693(84)91474-6}, Key = {art68} } @article{art67, Author = {Müller, U and Soff, G and Reinhardt, J and Reus, TD and Müller, B and Greiner, W}, Title = {Electron emission and positron production in deep inelastic heavy-ion reactions}, Journal = {Physical Review C - Nuclear Physics}, Volume = {30}, Number = {4}, Pages = {1199-1207}, Year = {1984}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.30.1199}, Abstract = {Atomic excitations are used to obtain information on the course of a nuclear reaction. Employing a semiclassical picture we calculate the emission of δ electrons and positrons in deep inelastic nuclear reactions for the example of U+U collisions incorporating nuclear trajectories resulting from two different nuclear friction models. The emission spectra exhibit characteristic deviations from those expected for elastic Coulomb scattering. The theoretical probabilities are compared with recent experimental data by Backe et al. A simple model is used to estimate the influence of a threebody breakup of the compound system upon atomic excitations. © 1984 The American Physical Society.}, Doi = {10.1103/PhysRevC.30.1199}, Key = {art67} } @article{art66, Author = {Heinz, U and Müller, U and Reinhardt, J and Müller, B and Greiner, W}, Title = {Time structure and atomic excltation spectra in heavy-ion collisions with nuclear contact}, Journal = {Annals of Physics}, Volume = {158}, Number = {2}, Pages = {476-512}, Year = {1984}, ISSN = {0003-4916}, Abstract = {From a quantum mechanical model for quasielastic nuclear scattering, employing a pocket in the internuclear potential at close distances, a distribution of nuclear delay times is derived. The influence of this time structure on atomic excitation spectra is demonstrated using positron emission from supercritical collisions as an example. In a narrow regime of beam energies close to the Coulomb barrier, a considerable probability for collisions with long nuclear delay times is found, associated with a sharp peak in the positron spectrum which is due to enhanced spontaneous positron production. It is pointed out that quasielastic nuclear scattering alone cannot account for the absolute numbers of spontaneous positrons as extracted from recent experiments. A possible generalization of the theory to include inelastic nuclear processes is briefly discussed. © 1984.}, Key = {art66} } @article{art65, Author = {Heinz, U and Reinhardt, J and Müller, B and Greiner, W and Pinkston, WT}, Title = {Nuclear time delay in resonant heavy ion collisions}, Volume = {316}, Number = {3}, Pages = {341-344}, Year = {1984}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01439906}, Abstract = {From a quantum mechanical model for quasielastic nuclear scattering, involving a pocket in the internuclear potential, we derive a distribution of nuclear delay times. We show that coherent excitation of states in a rotational band of nuclear resonances leads to a lighthouse effect in the nuclear scattering cross section. Its influence on atomic excitations is shortly discussed for the case of positron creation in supercritical heavy ion collisions. © 1984 Springer-Verlag.}, Doi = {10.1007/BF01439906}, Key = {art65} } @article{art64, Author = {Reus, THJD and Reinhardt, J and Muller, B and Greiner, W and Soff, G and Muller, U}, Title = {The influence of electron-electron interaction on inner-shell excitation processes in heavy-ion collisions}, Journal = {Journal of the Physics B: Atomic and Molecular Physics}, Volume = {17}, Number = {4}, Pages = {615-640}, Year = {1984}, ISSN = {0022-3700}, url = {http://dx.doi.org/10.1088/0022-3700/17/4/017}, Abstract = {The authors present calculations of electron excitation rates in heavy-ion collisions, in which the electron-electron interaction is treated within a relativistic self-consistent field approach. In comparison with earlier calculations neglecting electron shielding, the authors obtain increased probabilities for K-hole and delta -electron production, whereas the total positron yield decreases. Computed probabilities are compared with available experimental data.}, Doi = {10.1088/0022-3700/17/4/017}, Key = {art64} } @article{Schafer:1984pw, Author = {Schäfer, A and Müller, B and Greiner, W}, Title = {Spontaneous symmetry breaking in the presence of strong fields}, Journal = {Physics Letters B}, Volume = {149}, Number = {6}, Pages = {455-458}, Year = {1984}, ISSN = {0370-2693}, Abstract = {We analyse the properties of spontaneous symmetry breaking in the presence of external sources, concentrating on the question whether these sources can lead to a change of the vacuum expectation value of the Higgs field. We discuss in particular how the meaning of the Higgs-Kibble mechanisms is modified by such a vacuum change. The consequences of the presence of a strong electric charge are investigated in the framework of the Glashow-Salam-Weinberg model. Finally we discuss the possibility of actually observing this process. © 1984.}, Key = {Schafer:1984pw} } @article{Klevansky:1984by, Author = {Klevansky, SP and Muller, B and Greiner, W}, Title = {On the fission mechanism of an ellipsoidal MIT bag}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {10}, Number = {11}, Pages = {1487-1505}, Year = {1984}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/10/11/006}, Abstract = {The single-particle spectrum of a light quark moving in the field generated by a heavy quark-antiquark pair placed at the foci of an ellipsoidal bag is calculated in a variational approach. Residual interactions due to gluon exchange are accounted for in the random phase approximation (RPA). It is shown that the Tamm-Dancoff approximation (TDA) corresponding to the traditional semiclassical approach for a spherical cavity is inadequate for alpha s=2.2. In the spherical limit of an empty bag, the mass of the pion is underestimated in the RPA (85 MeV) as compared with an overestimate in the TDA (280 MeV). The RPA becomes unstable at a fixed deformation of the bag, for a constant value of alpha s. Employing Green function techniques, we show that this is an artefact signalling a phase transition from a filled Fermi vacuum to a correlated one. The presence of real quark-antiquark pairs within the ground state is interpreted as a signal that fission may occur.}, Doi = {10.1088/0305-4616/10/11/006}, Key = {Klevansky:1984by} } @article{art63, Author = {Reinhardt, J and Müller, B and Greiner, W and Müller, U}, Title = {Description of atomic excitations in heavy-ion reactions}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {28}, Number = {4}, Pages = {2558-2561}, Year = {1983}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.28.2558}, Abstract = {Excitations of the atomic shell in heavy-ion collisions are influenced by the presence of a nuclear reaction. In the present Rapid Communication we point out the equivalence between a semiclassical description based on the nuclear autocorrelation function with an earlier model which employs a distribution of reaction times f(T). For the example of U+U collisions, results of coupled-channel calculations for positron creation and K-hole excitations are discussed for two schematic reaction models. © 1983 The American Physical Society.}, Doi = {10.1103/PhysRevA.28.2558}, Key = {art63} } @article{art62, Author = {Heinz, U and Müller, B and Greiner, W}, Title = {Quantum mechanical treatment of electron-positron excitations in heavy ion collisions with nuclear contact}, Journal = {Annals of Physics}, Volume = {151}, Number = {1}, Pages = {227-261}, Year = {1983}, ISSN = {0003-4916}, Abstract = {A general theory is formulated of electron-positron excitations in heavy ion collisions with nuclear contact, treating the nuclear relative motion quantum mechanically. A set of coupled channel equations for the electronic occupation amplitudes is derived, which is formally very similar to the semiclassical theory based on a classical nuclear trajectory, and reduces to the latter in the JWKB approximation. The new coupled equations contain all the quantum mechanical information on the details of the nuclear scattering during nuclear contact. The importantce of this formulation for a quantitative theory of spontaneous positron creation in supercritical systems with nuclear time delay is pointed out. The possibility of line structures in the positron spectrum, as predicted semiclassically and recently discovered experimentally, is discussed in the framework of the DWBA approximation. For light-particle scattering off a nuclear resonance, the Blair formula for vacancy production is recovered in the same approximation. © 1983.}, Key = {art62} } @article{art61, Author = {Müller, B and Reinhardt, J and Greiner, W and Soff, G}, Title = {Critical remarks on a scaling law for inner-shell ionization}, Volume = {311}, Number = {3}, Pages = {151-155}, Year = {1983}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01415099}, Abstract = {In superheavy quasimolecules the number of created 1 sσ-vacancies per collisions P1sσ can be evaluated approximately by a simple scaling law. This analytical relation correctly reproduces the measured dependence of P1sσ on the impact parameter, bombarding energy and combined nuclear charge Z=Z1+Z2. It is emphasized, however, that the absolute ionization magnitude is underestimated typically by a factor of four. This discrepancy has been successfully resolved by the inclusion of multi-step excitation processes. It is shown that the derivation of the normalization constant in a scaling law previously reported by Armbruster's group is incorrect in the framework of first order perturbation theory. © 1983 Springer-Verlag.}, Doi = {10.1007/BF01415099}, Key = {art61} } @article{art60, Author = {Kirsch, J and Müller, B and Greiner, W}, Title = {Interference effects in MO X-ray spectra caused by nuclear sticking in superheavy quasimolecules}, Journal = {Physics Letters A}, Volume = {94}, Number = {3-4}, Pages = {151-155}, Year = {1983}, ISSN = {0375-9601}, Abstract = {Molecular orbital K X-rays emitted during Pb + Pb collisions are investigated assuming nuclear contact with sticking times of 10-19 s and 3 × 10-20 s, respectively. A peak in the differential radiation spectrum near the united-atom Kα line is obtained which becomes sharper with increasing delay time. The influence of the K-shell population on the spectrum is also investigated. © 1983.}, Key = {art60} } @article{art59, Author = {Schlüter, P and Reus, TD and Reinhardt, J and Müller, B and Soff, G}, Title = {Can the observed structures in positron spectra be caused by internal conversion?}, Volume = {314}, Number = {3}, Pages = {297-302}, Year = {1983}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01412925}, Abstract = {The energy distribution of positrons emitted in quasimolecular collisions of Uranium on Uranium and Uranium on Curium has been measured by several groups. Peak structures in the positron spectra were observed. We discuss the possibility that these structures originate from internal conversion processes following nuclear Coulomb excitation or transfer reactions. Consequences for the nuclear photon spectra and the δ-ray distribution are pointed out and experimental procedures for an unambiguous determination of the significance of conversion processes are discussed. © 1983 Springer-Verlag.}, Doi = {10.1007/BF01412925}, Key = {art59} } @article{art58, Author = {Heinz, U and Reinhardt, J and Müller, B and Greiner, W and Müller, U}, Title = {Beam energy dependence of spontaneous positron creation in delayed nuclear collisions}, Volume = {314}, Number = {1}, Pages = {125-126}, Year = {1983}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01411841}, Abstract = {We compute positron emission from U+Cm collisions within a quantum mechanical model for delayed nuclear collisions. We demonstrate a striking beam energy dependence of the strength of the spontaneous positron peak. © 1983 Springer-Verlag.}, Doi = {10.1007/BF01411841}, Key = {art58} } @article{art57, Author = {Müller, U and Soff, G and Reus, TD and Reinhardt, J and Müller, B and Greiner, W}, Title = {Positrons from supercritical fields of giant nuclear systems}, Volume = {313}, Number = {4}, Pages = {263-279}, Year = {1983}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01439478}, Abstract = {During collisions of heavy nuclei with a combined charge Z≳160 the electronic 1 s-state is deeply bound due to the strong Coulomb field, for Z≧173 it even enters as a resonance the lower continuum of the Dirac-Hamiltonian. In pure Rutherford scattering no qualitative indication for the filling of a dynamically created K-hole by the spontaneous positron creation process is predicted, but the study of heavy-ion collisions with nuclear time delay due to the attractive nuclear force promises clear signatures for the decay of the vacuum. Emphasis is laid also on the quantitative influence of the electron-electron interaction and of E0-transitions in the giant nuclear system on positron emission, the latter treated in a classical approximation. We compare our results with recent experimental data of two different groups at GSI, Darmstadt. © 1983 Springer-Verlag.}, Doi = {10.1007/BF01439478}, Key = {art57} } @article{Shanker:1983yd, Author = {Shanker, R and Vasak, D and Warke, CS and Greiner, W and Müller, B}, Title = {String-like solutions and regge trajectories in a cylindrically deformed quark bag model}, Journal = {Zeitschrift für Physik C-Particles and Fields}, Volume = {18}, Number = {4}, Pages = {327-340}, Year = {1983}, ISSN = {0170-9739}, url = {http://dx.doi.org/10.1007/BF01573734}, Abstract = {With the string picture in mind, we study quark bags of a simple fixed geometry: cylindrical. It is shown that the Dirac boundary value problem {Mathematical expression} of the M.I.T. bag model has no solutions, if this quark confinement condition is applied simultaneously on the radial walls as well as on the edges of the cylinder. By introducing a cruder condition, {Mathematical expression}, instead, but now only on the side walls, we calculate properties of non-strange baryons. A justification for the use of this cruder condition, {Mathematical expression}, on the side walls, instead of the proper M.I.T. condition, is then provided by showing that the M.I.T. "cylindrical" bag with smooth rounded corners gives essentially the same results, while being computationally more involved. Notwithstanding this departure from the M.I.T. confinement condition on the side walls, we find the following curious results: for high excitations, this bag attains string-like shapes. the sequence of baryonic states corresponding to pure single quark excitations fall on a linear Regge trajectory with a slope of ≈0.85 GeV-2. These trajectories hold at low-angular momenta. © 1983 Springer-Verlag.}, Doi = {10.1007/BF01573734}, Key = {Shanker:1983yd} } @article{Vasak:1983vm, Author = {Vasak, D and Wietschorke, K-H and Müller, B and Greiner, W}, Title = {Fission of bags by spontaneous quark-antiquark pair production in supercritical colour fields}, Journal = {Zeitschrift für Physik C-Particles and Fields}, Volume = {21}, Number = {1}, Pages = {119-125}, Year = {1983}, ISSN = {0170-9739}, url = {http://dx.doi.org/10.1007/BF01648786}, Abstract = {We describe the fission of heavy quarkonia as the decay of the bag vacuum state by spontaneous creation of a light quark-antiquark pair due to super-critical colour-electric fields. In the adiabatic approximation the heavy quarks are reduced to two point charges fixed at the foci of a prolate ellipsoidal MIT bag. We solve the Dirac equation with the corresponding quasi-abelian potential numerically and estimate the critical heavy-quark separation, at which the energy needed to produce the light quark pair approaches zero, to be 2.2 fm for the value 4αs/3=0.385 of the strong coupling constant and the vacuum pressure B1/4=235 MeV. These values have been used previously by Hasenfratz et al. to reproduce the spectra of heavy quarkonia. We show that this "critical distance" lies just above the classical turning point of those c {Mathematical expression}- and b {Mathematical expression}-resonances which are presently known. © 1983 Springer-Verlag.}, Doi = {10.1007/BF01648786}, Key = {Vasak:1983vm} } @article{Schafer:1983kc, Author = {Schäfer, A and Müller, B and Greiner, W}, Title = {New scheme for spontaneous symmetry breaking of color SU(3)}, Journal = {Physical Review Letters}, Volume = {50}, Number = {26}, Pages = {2047-2050}, Year = {1983}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.50.2047}, Abstract = {A new spontaneous-symmetry-breaking mechanism is formulated for SU(3), which is used to describe the formation of bags around quarks. The Higgs field is replaced by the scalar product of two colored fermion fields. This model gives mass only to one gluon (equivalent to Aμ8) when spontaneously broken. The consequences of this scheme are discussed, and it is argued that it can explain several puzzling high-energy heavy-ion experiments. © 1983 The American Physical Society.}, Doi = {10.1103/PhysRevLett.50.2047}, Key = {Schafer:1983kc} } @article{Vasak:1983an, Author = {Vasak, D and Shanker, R and Muller, B and Greiner, W}, Title = {Deformed solutions of the MIT quark bag model}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {9}, Number = {5}, Pages = {511-520}, Year = {1983}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/9/5/004}, Abstract = {The authors have solved the quark confinement boundary-value problem of the MIT bag model numerically for axially deformed bag shapes. As first results they present a Nilsson-type level diagram for quarks confined in a deformed cavity. Minimising the baryon energy with respect to the shape parameters, they also calculate the masses of baryonic states. Here the results show very clearly that excited baryon resonances are intrinsically deformed.}, Doi = {10.1088/0305-4616/9/5/004}, Key = {Vasak:1983an} } @article{art55, Author = {Soff, G and deReus, T and uuml, M and ller, B and Greiner, W}, Title = {Delta-electron production rates in the superheavy system Br+Pb}, Journal = {Phys. Lett. A}, Volume = {88}, Number = {8}, Pages = {398-399}, Year = {1982}, ISSN = {0375-9601}, Abstract = {A coincidence measurement between Î´-electrons and 1sÏƒ-vacancies in the heavy ion collision of 3579Br + 82208Pb is compared with absolute values of theoretical coupled channel results. Â© 1982.}, Key = {art55} } @article{art54, Author = {Soff, G and Schlüter, P and Müller, B and Greiner, W}, Title = {Self-energy of electrons in critical fields}, Journal = {Physical Review Letters}, Volume = {48}, Number = {21}, Pages = {1465-1468}, Year = {1982}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.48.1465}, Abstract = {The energy shift of K electrons in heavy atoms due to the self-energy correction has been calculated. This process is treated to all orders in Zα, where Z denotes the nuclear charge. For the superheavy system Z=170, where the K-shell binding energy reaches the pair-production threshold (E1sb∼2mc2), a shift of +11.0 keV is found. This shift is almost cancelled by the vacuum polarization, leaving a negligible effect for all quantum-electrodynamical corrections of order α but all orders of Zα. © 1982 The American Physical Society.}, Doi = {10.1103/PhysRevLett.48.1465}, Key = {art54} } @article{Rafelski:1982pu, Author = {Rafelski, J and Müller, B}, Title = {Strangeness production in the quark-gluon plasma}, Journal = {Physical Review Letters}, Volume = {48}, Number = {16}, Pages = {1066-1069}, Year = {1982}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.48.1066}, Abstract = {Rates are calculated for the processes gg→ss̄ and uū,dd̄→ss̄ in highly excited quarkgluon plasma. For temperature T>~160 MeV the strangeness abundance saturates during the lifetime (∼10-23 sec) of the plasma created in high-energy nuclear collisions. The chemical equilibration time for gluons and light quarks is found to be less than 10-24 sec. © 1982 The American Physical Society.}, Doi = {10.1103/PhysRevLett.48.1066}, Key = {Rafelski:1982pu} } @article{Muller:1982gd, Author = {Müller, B and Rafelski, J}, Title = {Role of internal symmetry in pp annihilation}, Journal = {Physics Letters B}, Volume = {116}, Number = {4}, Pages = {274-278}, Year = {1982}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(82)90341-0}, Abstract = {Internal symmetry influences the form of quantum spectra as well as the abundance of particles emitted by a thermal source. Isospin conservation in proton-antiproton annihilation is used to quantitatively illustrate the influence of these phenomena on mean pion multiplicities and the apparent primary pion temperature parameter. © 1982.}, Doi = {10.1016/0370-2693(82)90341-0}, Key = {Muller:1982gd} } @article{Shanker:1982rg, Author = {Shanker, R and Warke, CS and Greiner, W and Muller, B}, Title = {Cylindrical deformed quark bags}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {8}, Number = {4}, Pages = {L33-L38}, Year = {1982}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/8/4/001}, Abstract = {Presents approximate solutions of the MIT bag model for quarks in cylindrical bags. For a cylindrical bag surface it is found that Dirac's equation does not admit solutions corresponding to the linear boundary condition in psi = psi . It admits, nevertheless, solutions which satisfy the original confinement condition psi psi =0 exactly. The pressure balance condition is approximately satisfied through the variational minimisation of hadronic energy. These cylindrical quark bags to give not only the string limit of the bag model but also the correct slope of the leading Regge trajectory for baryons at the low angular momenta. States on a given trajectory differ from one another in axial-momentum excitations of a single quark.}, Doi = {10.1088/0305-4616/8/4/001}, Key = {Shanker:1982rg} } @article{Muller:1982db, Author = {uuml, M and ller, B and Rafelski, J}, Title = {Self-consistent gluon screening of a strong SU(2) source}, Journal = {Phys. Rev. D}, Volume = {25}, Pages = {566-572}, Year = {1982}, Key = {Muller:1982db} } @article{art56, Author = {Soffel, M and Müller, B and Greiner, W}, Title = {Stability and decay of the Dirac vacuum in external gauge fields}, Journal = {Physics Reports}, Volume = {85}, Number = {2}, Pages = {51-122}, Year = {1982}, ISSN = {0370-1573}, url = {http://dx.doi.org/10.1016/0370-1573(82)90129-6}, Abstract = {We consider various gauge fields coupled to the free Dirac equation according to symmetry principles. The gauge fields are treated as classical, unquantized fields. Sufficiently strong time-independent fields may give rise to spontaneous particle creation and to the decay of the symmetric Dirac vacuum into a new ground state with broken symmetry. The vacuum stability of the Dirac field is studied for the cases of external electromagnetic (U(1)), gravitational (Poincaré group including torsion) and Yang-Mills (SU(2)) potentials. © 1982.}, Doi = {10.1016/0370-1573(82)90129-6}, Key = {art56} } @article{fds304600, Author = {Soff, G and Reus, TD and Müller, B and Greiner, W}, Title = {δ-electron production rates in the superheavy system Br + Pb}, Journal = {Physics Letters A}, Volume = {88}, Number = {8}, Pages = {398-399}, Year = {1982}, ISSN = {0375-9601}, Abstract = {A coincidence measurement between δ-electrons and 1sσ-vacancies in the heavy ion collision of 3579Br + 82208Pb is compared with absolute values of theoretical coupled channel results. © 1982.}, Key = {fds304600} } @article{art53, Author = {Theis, J and uuml, M and ller, B}, Title = {Variational principle for an improved basis set for the description of scattering processes}, Journal = {Phys. Rev. A}, Volume = {24}, Pages = {89-96}, Year = {1981}, Key = {art53} } @article{art52, Author = {Alhassid, Y and uuml, M and ller, B and Koonin, SE}, Title = {Mean-field approximation for inclusive observables}, Journal = {Phys. Rev. C}, Volume = {23}, Pages = {487-491}, Year = {1981}, Key = {art52} } @article{art51, Author = {Soff, G and Müller, B and Greiner, W}, Title = {Systematics of inner-shell ionization in superheavy quasimolecules}, Volume = {299}, Number = {3}, Pages = {189-194}, Year = {1981}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01443935}, Abstract = {We present a detailed comparison of theoretical results on 1 sσ-ionization probabilities and δ-electron production rates with recent experimental data. The investigations are restricted to collisions of very heavy ions with (Z1+Z2)α≳1 below the Coulomb barrier. It is emphasized that first order time dependent perturbation theory is inapplicable for an accurate theoretical description of the measured data. © 1981 Springer-Verlag.}, Doi = {10.1007/BF01443935}, Key = {art51} } @article{art50, Author = {Heinz, U and Greiner, W and Müller, B}, Title = {Electron-translation effects in heavy-ion scattering}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {23}, Number = {2}, Pages = {562-596}, Year = {1981}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.23.562}, Abstract = {The origin and importance of electron-translation effects within a molecular description of electronic excitations in heavy-ion collisions is investigated. First, a fully consistent quantum-mechanical description of the scattering process is developed; the electrons are described by relativistic molecular orbitals, while the nuclear motion is approximated nonrelativistically. Leaving the quantum-mechanical level by using the semiclassical approximation for the nuclear motion, a set of coupled differential equations for the occupation amplitudes of the molecular orbitals is derived. In these coupled-channel equations the spurious asymptotic dynamical couplings are corrected for by additional matrix elements stemming from the electron translation. Hence, a molecular description of electronic excitations in heavy-ion scattering has been achieved, which is free from the spurious asymptotic couplings of the conventional perturbated stationary-state approach. The importance of electron-translation effects for continuum electrons and positrons is investigated. To this end an algorithm for the description of continuum electrons is proposed, which for the first time should allow for the calculation of angular distributions for δ electrons. Finally, the practical consequences of electron-translation effects are studied by calculating the corrected coupling matrix elements for the Pb-Cm system and comparing the corresponding K-vacancy probabilities with conventional calculations. We critically discuss conventional methods for cutting off the coupling matrix elements in coupled-channel calculations. © 1981 The American Physical Society.}, Doi = {10.1103/PhysRevA.23.562}, Key = {art50} } @article{art49, Author = {Reinhardt, J and Müller, U and Müller, B and Greiner, W}, Title = {The decay of the vacuum in the field of superheavy nuclear systems}, Volume = {303}, Number = {3}, Pages = {173-188}, Year = {1981}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01424757}, Abstract = {In the strong Coulomb field of a nucleus or quasimolecule with Z≳172 a change of the QED vacuum has been predicted, signalled by the spontaneous emission of positrons if holes in the K-shell are available. The dynamical semiclassical theory of positron excitation in heavy ion scattering is presented and extended to collisions with nuclear contact. Interference patterns in the energy spectrum of the emitted positrons and, for sufficiently long reaction time T, the emerging of a characteristic line at the position of the 1 sσ-resonance is predicted. The position and width of the 1 sσ-resonance is calculated in dependence on the nuclear configuration, the effect of electron screening is taken into account. Recent experimental indications [1, 2] for structures in the spectra of positrons emitted in U-U collisions at energies close to the Coulomb barrier are discussed in terms of spontaneous positron creation. The observed spectra could be explained under the assumption of long lasting nuclear reactions (T≳4·10-20 s) with a cross section in the millibarn region. Various consequences of this interpretation are discussed. © 1981 Springer-Verlag.}, Doi = {10.1007/BF01424757}, Key = {art49} } @article{art48, Author = {Gärtner, P and Heinz, U and Müller, B and Greiner, W}, Title = {Limiting charge for electrostatic point sources}, Volume = {300}, Number = {2-3}, Pages = {143-155}, Year = {1981}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01412291}, Abstract = {We investigate the behaviour of the vacuum charge around a supercritical nucleus with Z>137 in dependence on the nuclear radius. The screening effects are considered in a quasiclassical approximation. We show that in the point nucleus limit the nuclear charge is screened by the vacuum charge up to Z=137. This means that the coupling strength of a point charge in QED cannot be larger than 1. The influence of the heavier leptons is also discussed. © 1981 Springer-Verlag.}, Doi = {10.1007/BF01412291}, Key = {art48} } @article{art47, Author = {Reinhardt, J and Müller, B and Greiner, W}, Title = {Theory of positron production in heavy-ion collisions}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {24}, Number = {1}, Pages = {103-128}, Year = {1981}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.24.103}, Abstract = {Collisions of very heavy ions at energies close to the Coulomb barrier are discussed as a unique tool to study the behavior of the electron-positron field in the presence of strong external electromagnetic fields. To calculate the excitation processes induced by the collision dynamics, a semiclassical model is employed and adapted to describe the field-theoretical many-particle system. An expansion in the adiabatic molecular basis is chosen. Energies and matrix elements are calculated using the monopole approximation. In a supercritical (Z1+Z2173) quasiatomic system the 1s level joins the antiparticle continuum and becomes a resonance, rendering the neutral vacuum state unstable. Several methods of treating the corresponding time-dependent problem are discussed. A projection-operator technique is introduced for a fully dynamical treatment of the resonance. Positron excitation rates in s12 and p12 states are obtained by numerical solution of the coupled-channel equations and are compared with results from first- plus second-order perturbation theory. Calculations are performed for subcritical and supercritical collisions of Pb-Pb, Pb-U, U-U, and U-Cf. Strong relativistic deformations of the wave functions and the growing contributions from inner-shell bound states lead to a very steep Z dependence of positron production. The results are compared with available data from experiments done at GSI. Correlations between electrons and positrons are briefly discussed. © 1981 The American Physical Society.}, Doi = {10.1103/PhysRevA.24.103}, Key = {art47} } @article{Muller:1981kf, Author = {Müller, B and Rafelski, J}, Title = {Temperature dependence of the bag constant and the effective lagrangian for gauge fields at finite temperatures}, Journal = {Physics Letters B}, Volume = {101}, Number = {1-2}, Pages = {111-118}, Year = {1981}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(81)90502-5}, Abstract = {We calculate the free energy for a gauge field at finite temperature in the presence of a constant gauge magnetic field in the one-loop approximation, omitting unstable modes. The effect of finite temperature on the approximate "true" Savvidy ground state of QCD is derived. A phase transition to the perturbative ground state at Tcr=1.5Bs 1 4 ≈210 MeV is found. © 1981.}, Doi = {10.1016/0370-2693(81)90502-5}, Key = {Muller:1981kf} } @article{Schmidt:1981xp, Author = {Schmidt, G and Greiner, W and Heinz, UW and uuml, M and ller, B}, Title = {Stability of massive objects in a new scalar-tensor theory}, Journal = {Phys. Rev.}, Volume = {D24}, Pages = {1484-1490}, Year = {1981}, Key = {Schmidt:1981xp} } @article{fds247201, Author = {Reinhardt, J and Soff, G and Müller, B and Greiner, W}, Title = {Dynamical aspects: Coherent production of positrons in heavy ion collisions}, Journal = {Progress in Particle and Nuclear Physics}, Volume = {4}, Number = {C}, Pages = {547-578}, Year = {1980}, ISSN = {0146-6410}, Abstract = {Collisions of very heavy ions are discussed as a means to investigate quantum electrodynamics in the presence of strong external fields. The action of the combined Coulomb field of the closely approaching nuclei leads to strong binding of the inner electron shells and to large induced transitions. The resulting mechanisms for the production of positrons are discussed in detail and compared with recent experiments. The importance of multi-step excitations is stressed and first results of coupled channel calculations are presented. © 1980.}, Key = {fds247201} } @article{fds247202, Author = {Reinhardt, J and Müller, B and Greiner, W}, Title = {Quantum electrodynamics of strong fields in heavy ion collision}, Journal = {Progress in Particle and Nuclear Physics}, Volume = {4}, Number = {C}, Pages = {503-545}, Year = {1980}, ISSN = {0146-6410}, Abstract = {Quantum Electrodynamics of strong external fields is discussed in the context of atomic physics. For sufficiently large electromagnetic coupling constant Zα bound states can approach and even join the antiparticle continuum of the Dirac equation. The resulting possibility of spontaneous positron production and the new concept of a charged electron-positron-vacuum is discussed. The autoionization model and the exact solutions of the single particle Dirac equation are supplemented by a quantum-field-theoretical approach. The influence of vacuum polarization, possible non-linear field effects and the self-screening of extremely strong electrical charges are investigated. © 1980.}, Key = {fds247202} } @article{art46, Author = {Müller, U and Reinhardt, J and Soff, G and Müller, B and Greiner, W}, Title = {K-vacancy formation in deep inelastic nuclear reactions}, Volume = {297}, Number = {4}, Pages = {357-358}, Year = {1980}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01422798}, Abstract = {We investigate the dependence of inner shell vacancy production on interaction time T in deep inelastic nuclear reactions. Coupled channel calculations for Xe-Pb, Pb-Pb, and U-U collisions are presented. In the heaviest system strong interference minima for both 1sσ and 2p1/2σ excitation are predicted at T≲3.10-21 sec. © 1980 Springer-Verlag.}, Doi = {10.1007/BF01422798}, Key = {art46} } @article{art45, Author = {uuml, M and ller, B and Oberacker, V}, Title = {Influence of nuclear trajectory variations on atomic excitation probabilities}, Journal = {Phys. Rev. C}, Volume = {22}, Pages = {1909-1913}, Year = {1980}, Key = {art45} } @article{art44, Author = {Soff, G and Reinhardt, J and Müller, B and Greiner, W}, Title = {Coupled channel analysis of inner-shell vacancy formation in superheavy quasimolecules}, Volume = {294}, Number = {2}, Pages = {137-147}, Year = {1980}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01435048}, Abstract = {We calculate the ionization probability of the quasimolecular 1 sσ-state in collisions of very heavy ions with (Z1+Z2) α≳1. Multistep excitation processes between bound and continuum states are investigated. Due to the multistep processes the number of created 1 sσ-vacancies is typically increased by a factor 2-5 over that obtained within time-dependent perturbation theory (i.e. the one-step processes). Some implications of the many-electron problem and the Pauli principle are discussed. The δ-electron distribution is compared with recent experimental data. © 1980 Springer-Verlag.}, Doi = {10.1007/BF01435048}, Key = {art44} } @article{art43, Author = {Kirsch, J and uuml, M and ller, B and Greiner, W}, Title = {Unified theory of electrons and photons in heavy ion collisions}, Journal = {Z. Naturforsch.}, Volume = {35a}, Pages = {579-589}, Year = {1980}, Key = {art43} } @article{art42, Author = {auml, G and rtner, P and uuml, M and ller, B and Reinhardt, J and Greiner, W}, Title = {Limiting charge for point nuclei}, Journal = {Phys. Lett. B}, Volume = {95}, Pages = {181-184}, Year = {1980}, Key = {art42} } @article{art41, Author = {uuml, M and ller, B}, Title = {Some comments on the relativistic Thomas-Fermi model}, Journal = {Phys. Lett. B}, Volume = {94}, Pages = {275-276}, Year = {1980}, Key = {art41} } @article{Vasak:1980sg, Author = {Vasak, D and uuml, M and ller, B and Greiner, W}, Title = {Pion radiation from fast heavy ions}, Journal = {Phys. Scripta}, Volume = {22}, Pages = {25-35}, Year = {1980}, Key = {Vasak:1980sg} } @article{Vasak:1980eu, Author = {Vasak, D and Stöcker, H and Müller, B and Greiner, W}, Title = {Pion bremsstrahlung and critical phenomena in relativistic nuclear collisions}, Journal = {Physics Letters B}, Volume = {93}, Number = {3}, Pages = {243-246}, Year = {1980}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(80)90504-3}, Abstract = {We investigate the dependence of pion bremsstrahlung on the deceleration of the nuclei in relativistic heavy ion collisions. The vicinity of an abnormal phase in nuclear matter can lead - owing to critical N-N scattering - to faster deceleration or decreasing transparency of the nuclei. This would result in a threshold enhancement of the pion bremsstrahlung cross section, which in turn can be used to search for abnormal nuclear states experimentally. © 1980.}, Doi = {10.1016/0370-2693(80)90504-3}, Key = {Vasak:1980eu} } @article{Hofmann:1980rj, Author = {Hofmann, J and Müller, B and Greiner, W}, Title = {Phase transitions in nuclear matter}, Journal = {Physical Review C - Nuclear Physics}, Volume = {22}, Number = {1}, Pages = {221-228}, Year = {1980}, ISSN = {0556-2813}, url = {http://dx.doi.org/10.1103/PhysRevC.22.221}, Abstract = {A method for the description of spin-isospin phase transitions in nuclear matter is developed. It allows a complete description of the pion condensation phase transition in the framework of the Landau-Migdal Fermi liquid theory. The equation of the order parameter is derived and the condensation energy is calculated. We study the influence of pion condensation on the nuclear equation of state and the temperature dependence of pion condensation. NUCLEAR STRUCTURE Description of pion-condensed ground state by Green's function technique. © 1980 The American Physical Society.}, Doi = {10.1103/PhysRevC.22.221}, Key = {Hofmann:1980rj} } @article{Soffel:1980kj, Author = {Soffel, M and Müller, B and Greiner, W}, Title = {Radiation and the structure of space-time}, Journal = {General Relativity and Gravitation}, Volume = {12}, Number = {4}, Pages = {287-303}, Year = {1980}, ISSN = {0001-7701}, url = {http://dx.doi.org/10.1007/BF00756619}, Abstract = {The classical bremsstrahlung problem is discussed with respect to the global structure of space-time. Various physical phenomena (such as the Hawking effect, etc.) connected with the large-scale structure of space-time are mentioned. © 1980 Plenum Publishing Corporation.}, Doi = {10.1007/BF00756619}, Key = {Soffel:1980kj} } @article{Soffel:1980kx, Author = {Soffel, M and uuml, M and ller, B and Greiner, W}, Title = {Dirac particles in Rindler space}, Journal = {Phys. Rev. D}, Volume = {22}, Pages = {1935-1937}, Year = {1980}, Key = {Soffel:1980kx} } @article{Schafer:1980bg, Author = {Schäfer, W and Stöcker, H and Müller, B and Greiner, W}, Title = {Mach-shock electron distributions from solids}, Volume = {36}, Number = {4}, Pages = {319-322}, Year = {1980}, ISSN = {0340-224X}, url = {http://dx.doi.org/10.1007/BF01322154}, Abstract = {Heavy ion induced density fluctuations in the electron plasma of solids known as wakes show the characteristic features of Mach-shock waves. We propose a method to detect the electron wake in solid state materials by measuring the angular distribution of emitted electrons of low energy. These show up as distinct maxima at certain angles. In the emission angle we find an increase with bombarding energy, following the Mach relation cos Θem=vs/v0. © 1980 Springer-Verlag.}, Doi = {10.1007/BF01322154}, Key = {Schafer:1980bg} } @article{fds247200, Author = {Kessel, QC and Morgenstern, R and Müller, B and Niehaus, A}, Title = {Angular correlation between autoionization electrons and scattered ions in 2000-eV He+-He collisions}, Journal = {Physical Review A - Atomic, Molecular, and Optical Physics}, Volume = {20}, Number = {3}, Pages = {804-813}, Year = {1979}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.20.804}, Abstract = {Complex population amplitudes for the excitation of magnetic sublevels of He(2p2)D1 and He(2s2p)P1 states in 2-keV He+ -He collisions have been determined by measuring the energy spectra of the corresponding autoionization electrons ejected at different angles in coincidence with the inelastically scattered ions. It was found that He(2p2)D1 is excited with a relative probability of 97%. If the direction of the internuclear line at the distance of closest approach is taken as z axis, we find that primarily the m=0 sublevel is populated and that the complete D1 excitation can be interpreted as due to pure m=0 excitations with respect to momentary internuclear lines at different points of the trajectory which are symmetric to the turning point. These results are discussed within the framework of the Fano-Lichten promotion model. Quantization along an axis perpendicular to the scattering plane shows an orientation of the excited D1 state. From this we find that the angular momentum Ly transferred from the motion of the heavy particles to the electron cloud has an expectation value of Ly-. © 1979 The American Physical Society.}, Doi = {10.1103/PhysRevA.20.804}, Key = {fds247200} } @article{art40, Author = {Hofmann, J and Müller, B and Greiner, W}, Title = {Phase transitions and shock waves in nuclei}, Journal = {Physics Letters B}, Volume = {82}, Number = {2}, Pages = {195-198}, Year = {1979}, ISSN = {0370-2693}, Abstract = {In the present paper we investigate the compatibility of shock waves and phase transitions in nuclear matter. We show, that a continuous phase transition, i.e. the coexistence of the two phases, is not compatible with the existence of a sharp shock front. In this case shock waves become hydrodynamically unstable which may lead to a suppression of shock phenomena in certain energy windows in high energy heavy ion collisions. © 1979.}, Key = {art40} } @article{art39, Author = {Müller, A and Müller, B and Greiner, W}, Title = {Cosmological particle production}, Journal = {Physics Letters A}, Volume = {74}, Number = {3-4}, Pages = {281-284}, Year = {1979}, ISSN = {0375-9601}, Abstract = {We apply the WKB approximation of path integrals to pair creation in expanding universes. Friedman cosmologies for arbitrary equations of state p = αρ{variant} are discussed. Observational data are in favor of a stiff equation of state (p ∼ ρ{variant}). © 1979.}, Key = {art39} } @article{art38, Author = {Soff, G and Reinhardt, J and uuml, M and ller, B and Greiner, W}, Title = {Delta-electron emission in deep-inelastic heavy ion collisions}, Journal = {Phys. Rev. Lett.}, Volume = {43}, Pages = {1981-1984}, Year = {1979}, Key = {art38} } @article{art37, Author = {Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Role of multistep processes in heavy-ion inner-shell excitations}, Journal = {Physical Review Letters}, Volume = {43}, Number = {18}, Pages = {1307-1310}, Year = {1979}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.43.1307}, Abstract = {This Letter discusses inner-shell excitation in collisions of very heavy ions (Z1+Z2140) in the framework of the quasimolecular model. The importance of multistep excitations and of coupling between continuum states is demonstrated. The 1sσ vacancy probabilities resulting from coupled-channels calculations exceed perturbation theory by a factor 3-5, thus giving good agreement with recent experimental results. © 1979 The American Physical Society.}, Doi = {10.1103/PhysRevLett.43.1307}, Key = {art37} } @article{art36, Author = {Kirsch, J and Betz, W and Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {The impact parameter dependence of the Pb + Pb K - MO spectrum}, Volume = {292}, Number = {3}, Pages = {227-234}, Year = {1979}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01547466}, Abstract = {Molecular orbital X-rays are emitted during ion-atom collisions. The theoretical treatment, numerical results for the Pb + Pb system and a comparison with background radiation like NNB, SEB and γ-decay of Coulomb excited nuclei are presented. © 1979 Springer-Verlag.}, Doi = {10.1007/BF01547466}, Key = {art36} } @article{art35, Author = {Reinhardt, J and Müller, B and Greiner, W and Soff, G}, Title = {Delta electrons: An atomic clock for deep inelastic collisions}, Volume = {292}, Number = {2}, Pages = {211-212}, Year = {1979}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01441628}, Abstract = {We calculate the δ-electron distribution resulting from heavy ion collisions with projectile energies above the Coulomb barrier. It is shown that the life time (Δτ≳10-21s) of superheavy composite systems causes pronounced oscillations in the electron spectrum. The width of the oscillations is found to be ΔE=h/Δτ. This effect can be used to measure nuclear sticking times quite accurately. © 1979 Springer-Verlag.}, Doi = {10.1007/BF01441628}, Key = {art35} } @article{art34, Author = {Theis, J and Reinhardt, J and Muller, B}, Title = {How good is the adiabatic basis in heavy ion collisions?}, Journal = {Journal of the Physics B: Atomic and Molecular Physics}, Volume = {12}, Number = {16}, Pages = {L479-L483}, Year = {1979}, ISSN = {0022-3700}, url = {http://dx.doi.org/10.1088/0022-3700/12/16/001}, Abstract = {Discusses the optimal choice of the basis for calculations of inner-shell excitations in the collision of heavy ions. Starting from a variational principle which minimises the time-integrated coupling strength, a relation between a model two-centre distance and the actual internuclear separation is derived. For 1s sigma excitations in Pb-Pb collisions it is found that the optimal basis is almost identical to the adiabatic one. For higher quantum states the adiabatic treatment becomes less adequate.}, Doi = {10.1088/0022-3700/12/16/001}, Key = {art34} } @article{art33, Author = {Soff, G and Greiner, W and Betz, W and uuml, M and ller, B}, Title = {Electrons in superheavy quasimolecules}, Journal = {Phys. Rev. A}, Volume = {20}, Pages = {169-193}, Year = {1979}, Key = {art33} } @article{art32, Author = {Rihan, TH and Muller, B and Greiner, W}, Title = {On the adequacy of first-order perturbation theory for calculations of inner-shell ionisation}, Journal = {Journal of the Physics B: Atomic and Molecular Physics}, Volume = {12}, Number = {5}, Pages = {761-774}, Year = {1979}, ISSN = {0022-3700}, url = {http://dx.doi.org/10.1088/0022-3700/12/5/020}, Abstract = {Transition probabilities for inner-shell electrons during the formation of quasi-molecular systems in heavy-ion collisions are considered. The effect of transitions to the continuum on discrete transition probabilities is given via a simple prescription satisfying unitarity. In this way, it is also shown that the direct ionisation probabilities will be modified by virtual transitions to the continuum. Adopting a scaling model and the authors' prescription, the effect of such virtual processes on the ionisation of 1s sigma electrons can be calculated analytically. As an example, the authors calculated it for the Pb-Pb quasi-molecular system. It is found that such virtual processes suppress the direct 1s sigma ionisation probability for large impact parameters and/or small relative ion velocities.}, Doi = {10.1088/0022-3700/12/5/020}, Key = {art32} } @article{art31, Author = {wietschorke, K-H and Muller, B and Greiner, W and Soff, G}, Title = {Self-consistent determination of critical two-centre distances}, Journal = {Journal of the Physics B: Atomic and Molecular Physics}, Volume = {12}, Number = {1}, Pages = {L31-L33}, Year = {1979}, ISSN = {0022-3700}, url = {http://dx.doi.org/10.1088/0022-3700/12/1/007}, Abstract = {In collisions of very heavy ions (Z1+Z2 greater than 173) the binding energy of the quasimolecular 1s sigma state may exceed twice the electron rest mass. The critical internuclear separation is calculated within the relativistic Hartree-Fock-Slater model. For the almost neutral U-U system, the authors obtained Rcr=26 fm.}, Doi = {10.1088/0022-3700/12/1/007}, Key = {art31} } @article{Soffel:1979ma, Author = {Soffel, M and Müller, B and Greiner, W}, Title = {Vacuum with spin in the ecsk-theory of gravitation}, Journal = {Physics Letters A}, Volume = {70}, Number = {3}, Pages = {167-170}, Year = {1979}, ISSN = {0375-9601}, Abstract = {The decay of the isotropic spin 1/2 particle-antiparticle vaccum in an external torsion field is shown. For very high torsion fields the overcritical vacuum is described in a statistical model. © 1979.}, Key = {Soffel:1979ma} } @article{fds247199, Author = {Kessel, QC and Morgenstern, R and Müller, B and Niehaus, A and Thielmann, U}, Title = {Ion-electron coincidence measurements of the azimuthal dependence of electrons from autoionizing He atoms excited in 2000-eV He+-He collisions}, Journal = {Physical Review Letters}, Volume = {40}, Number = {10}, Pages = {645-648}, Year = {1978}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.40.645}, Abstract = {The azimuthal angular dependence and corresponding energy spectra have been measured for electrons ejected at 135° from the beam direction by autoionizing He atoms in the (2p2)D1 and (2s2p)P1 states, which were excited by 2000-eV He+ ions scattered through 6°. The data show a marked dependence on the azimuthal angle of the scattered projectile and are used to calculate the moduli and phases of the population amplitudes of the magnetic sublevels excited. © 1978 The American Physical Society.}, Doi = {10.1103/PhysRevLett.40.645}, Key = {fds247199} } @article{art30, Author = {Muller, A and Heinz, U and Muller, B and Greiner, W}, Title = {On gravitation theories with limiting curvature}, Volume = {11}, Number = {9}, Pages = {1781-1798}, Year = {1978}, ISSN = {0022-3689}, url = {http://dx.doi.org/10.1088/0305-4470/11/9/012}, Abstract = {The authors discuss the solutions of the generalised gravitational field equations derived from the nonlinear Lagrangian for a limiting curvature theory and compare the free space solutions as well as the solutions for an extended star with the corresponding solutions of the Einstein equations.}, Doi = {10.1088/0305-4470/11/9/012}, Key = {art30} } @article{art29, Author = {Soff, G and uuml, M and ller, B and Greiner, W}, Title = {Spectroscopy of electronic states in superheavy quasimolecules}, Journal = {Phys. Rev. Lett.}, Volume = {40}, Pages = {540-544}, Year = {1978}, Key = {art29} } @article{art28, Author = {Rihan, TH and Aly, NS and Merzbacher, E and Müller, B and Greiner, W}, Title = {Relaxation times in intermediate quasi-molecules}, Volume = {285}, Number = {4}, Pages = {397-403}, Year = {1978}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01813240}, Abstract = {The influence of perturbative interactions is discussed in the frame-work of time-dependent perturbation theory. A characteristic time (to be called relaxation time), during which a given initial state of the system will be depleted, is defined. In case this relaxation time is smaller than the collision time of the process, the usual adiabatic perturbation treatment becomes vague. In this sense, the usefulness of various approaches to the problem, such as those based on two-center Dirac wave functions or Hartree-Fock states can be quantitatively investigated. Calculations based on two-center Dirac wave functions and a restricted quasimolecular configuration for the electronic system in U-U collisions, reveal that the electron-electron interactions can be safely neglected for the inner-shell electronic states. A prescription is given to obtain more reliable transition probabilities when the adiabatic perturbation treatment fails. It is shown that unitarity is recovered in such a prescription. © 1978 Springer-Verlag.}, Doi = {10.1007/BF01813240}, Key = {art28} } @article{art27, Author = {Kirsch, J and Betz, W and Reinhardt, J and Soff, G and Müller, B and Greiner, W}, Title = {K-X-ray spectrum of the Pb + Pb quasimolecules}, Journal = {Physics Letters B}, Volume = {72}, Number = {3}, Pages = {298-302}, Year = {1978}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(78)90123-5}, Abstract = {We present ab initio calculations of the quasimolecular K-X-ray spectrum from the Pb + Pb system, where both the Kd-hole amplitude and the radiation amplitude is calculated in first order perturbation theory. A comparison with the background radiation like NNB, SEB and γ-decay of excited nuclei shows that the molecular X-rays should be measurable up to X-ray energies corresponding to the characteristic K-line of the united superheavy atom. © 1978.}, Doi = {10.1016/0370-2693(78)90123-5}, Key = {art27} } @article{art26, Author = {Soff, G and Betz, W and Müller, B and Greiner, W and Merzbacher, E}, Title = {Inner shell ionization in the Pb-Pb quasimolecule}, Journal = {Physics Letters A}, Volume = {65}, Number = {1}, Pages = {19-22}, Year = {1978}, ISSN = {0375-9601}, Abstract = {Direct ionization of the 1sσ, 2sσ, 3sσ and 2p 1 2σ electronic states via radial coupling in the Pb-Pb quasimolecule is investigated as function of the impact parameter b. The ionization probability decreases exponentially like P(b)∼exp(- b a), with a1sσ=19 fm, a2sσ=76 fm, a3sσ=135 fm and a2p 1 2σ=47 fm. The high-energy part of the electronic spectrum is dominated by 2sσ and 2p 1 2σ ionization. As total ionization cross section we find σ1sσ=2 barn and σ2p 1 2σ=59 barn for E1ab=1210 MeV. © 1978.}, Key = {art26} } @article{art25, Author = {Heiligenthal, G and Betz, W and Soff, G and Müller, B and Greiner, W}, Title = {The influence of rotational coupling on K-vacancy formation in U-Pb collisions}, Volume = {285}, Number = {1}, Pages = {105-106}, Year = {1978}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01410233}, Abstract = {The probability for 2p1/2σ-ionization in U-U and Pb-Pb collisions is calculated. The results are used to explain the measured impact parameter dependence for K-vacancy production in U-Pb collisions as the sum of direct ionization and strong rotational and radial coupling between the substates of the quasimolecular L-shell. © 1978 Springer-Verlag.}, Doi = {10.1007/BF01410233}, Key = {art25} } @article{art24, Author = {Müller, B and Soff, G and Greiner, W and Ceausescu, V}, Title = {Scaling behaviour of inner-shell ionization in superheavy quasi-molecules}, Volume = {285}, Number = {1}, Pages = {27-30}, Year = {1978}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01410218}, Abstract = {We derive an approximate analytical formula for the K-shell ionization in collisions of very heavy atoms. The impact parameter and bombarding energy dependence are well described. The binding energy of the bound state at closest approach enters in a simple way, which could provide an experimental method for a spectroscopy of quasimolecular states. © 1978 Springer-Verlag.}, Doi = {10.1007/BF01410218}, Key = {art24} } @article{Reinhardt:1978cy, Author = {Reinhardt, J and Oberacker, V and Müller, B and Greiner, W and Soff, G}, Title = {Positron emission in PbPb and PbU collisions}, Journal = {Physics Letters B}, Volume = {78}, Number = {2-3}, Pages = {183-188}, Year = {1978}, ISSN = {0370-2693}, Abstract = {We present quantitative calculations of positron emission dynamically induced in the collision of PbPb and PbU. The results are compared with recent measurements, yielding evidence for new processes characteristic for quantum electrodynamics of strong fields. © 1978.}, Key = {Reinhardt:1978cy} } @article{Rafelski:1978xy, Author = {Rafelski, J and Müller, B and Greiner, W}, Title = {Spontaneous vacuum decay of supercritical nuclear composites}, Volume = {285}, Number = {1}, Pages = {49-52}, Year = {1978}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01410223}, Abstract = {We show that in deep inelastic heavy ion collisions with Z1+Z2> 173 the spontaneous decay of the neutral vacuum by emission of positrons may be isolated from other competing positron producing processes. From the details of the spontaneous positron spectrum information about the nature (lifetime, shape and angular momentum) of the composite nuclear system may be derived. © 1978 Springer-Verlag.}, Doi = {10.1007/BF01410223}, Key = {Rafelski:1978xy} } @article{Schafer:1978jq, Author = {Schäfer, W and Stöcker, H and Müller, B and Greiner, W}, Title = {Mach cones induced by fast heavy ions in electron plasma}, Volume = {288}, Number = {4}, Pages = {349-352}, Year = {1978}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01417717}, Abstract = {Fast heavy ions penetrating through solids initiate density oscillations of the electron plasma, forming Mach cones if the projectile velocity exceeds a critical value cs. These Mach waves should lead to the directed emission of electrons from the target. The preferential emission angle θ{symbol} as a function of the bombarding energy is calculated for various projectile-target combinations. © 1978 Springer-Verlag.}, Doi = {10.1007/BF01417717}, Key = {Schafer:1978jq} } @article{Soffel:1978un, Author = {Soffel, M and Heinz, U and Müller, B and Greiner, W}, Title = {A self-consistent solution of the coupled Dirac-Einstein equations in the mean-field Hartree approximation}, Journal = {Lettere al Nuovo Cimento Series 2}, Volume = {22}, Number = {10}, Pages = {391-396}, Year = {1978}, ISSN = {0375-930X}, url = {http://dx.doi.org/10.1007/BF02856155}, Doi = {10.1007/BF02856155}, Key = {Soffel:1978un} } @article{Greiner:1978xq, Author = {Greiner, W and Müller, B and Soff, G}, Title = {Delta electrons as a probe of strong magnetic fields in heavy ion collisions}, Journal = {Physics Letters A}, Volume = {69}, Number = {1}, Pages = {27-30}, Year = {1978}, ISSN = {0375-9601}, Abstract = {We propose that the spin polarization of delta electrons should be used as a measure of the strong magnetic fields (B∼1017 G) induced by the nuclear motion in collisions of very heavy ions. The polarization is typically of the order of 10-20 percent in Pb-Pb and U-U collisions. We also discuss the bombarding energy dependence up to E1ab = 200MeV/u, where 500 keV level splitting between spin up and down states is obtained. © 1978.}, Key = {Greiner:1978xq} } @article{fds304586, Author = {Fink, HJ and Muller, B and Greiner, W}, Title = {Parastatistics as an effective description of complex particles (nucleus-nucleus collisions and muonic atoms)}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {3}, Number = {8}, Pages = {1119-1131}, Year = {1977}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/3/8/021}, Abstract = {Parastatistics with continuous order are proposed. The various parastatistics are used in scattering theory as an effective description accounting for the internal structure of composite particles (nuclei). Also investigated is the possibility that muons are (composite) para-particles.}, Doi = {10.1088/0305-4616/3/8/021}, Key = {fds304586} } @article{art23, Author = {Müller, B and Greiner, W and Rafelski, J}, Title = {Interpretation of external fields as temperature}, Journal = {Physics Letters A}, Volume = {63}, Number = {3}, Pages = {181-183}, Year = {1977}, ISSN = {0375-9601}, Abstract = {We show that average excitation of the vacuum state in the presence of an external electric field can be described by an effective temperature kT = eE (2πm). We present a qualitative generalization of our result to other interactions. Some phenomenological implications concerning matter at low temperatures in strong electric fields (105 V/cm) are offered. © 1977.}, Key = {art23} } @article{art22, Author = {Fink, HJ and uuml, M and ller, B and Greiner, W}, Title = {Parastatistics as an effective description of complex particles}, Journal = {J. Phys. G}, Volume = {3}, Number = {8}, Pages = {1119-1131}, Year = {1977}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/3/8/021}, Abstract = {Parastatistics with continuous order are proposed. The various parastatistics are used in scattering theory as an effective description accounting for the internal structure of composite particles (nuclei). Also investigated is the possibility that muons are (composite) para-particles.}, Doi = {10.1088/0305-4616/3/8/021}, Key = {art22} } @article{art21, Author = {Soff, G and Müller, B}, Title = {Transition rates of electrons in superheavy elements}, Volume = {280}, Number = {3}, Pages = {243-247}, Year = {1977}, ISSN = {0340-2193}, url = {http://dx.doi.org/10.1007/BF01434348}, Abstract = {Transition rates for electrons in the superheavy elements Z=114, 126, 134, 145, 164 and 173 are calculated. K, L and M-shells are considered as final states. The 2 s-1 s transition of multipolarity M 1 is dominant for Z = 173 with a transition time of 10-18 s. The radical expectation values 〈r〉 and 〈r2〉1/2 are given. © 1977 Springer-Verlag.}, Doi = {10.1007/BF01434348}, Key = {art21} } @article{art20, Author = {Soff, G and lustig, H-J and Muller, B}, Title = {On the identification of superheavy elements from L and M spectra}, Journal = {Journal of Physics G: Nuclear Physics}, Volume = {3}, Number = {4}, Pages = {583-590}, Year = {1977}, ISSN = {0305-4616}, url = {http://dx.doi.org/10.1088/0305-4616/3/4/018}, Abstract = {Various possibilities for interpreting the recently observed X-rays from supposedly superheavy elements are studied. These X-rays can also be explained by atomic lines of superheavy elements from the Z=164 and Z=114 islands.}, Doi = {10.1088/0305-4616/3/4/018}, Key = {art20} } @article{art19, Author = {Soff, G and Reinhardt, J and Müller, B and Greiner, W}, Title = {Shakeoff of the vacuum polarization in quasimolecular collisions of very heavy ions}, Journal = {Physical Review Letters}, Volume = {38}, Number = {11}, Pages = {592-595}, Year = {1977}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.38.592}, Abstract = {The theory of direct electron-positron pair production in the collision of heavy ions is formulated in the framework of the quasimolecular model. The pair production process acquires a collective nature for (Z1+Z2)>1 and can be understood as the shakeoff of the strong vacuum polarization cloud formed in the quasimolecule. The total cross section is, e.g., 76 b for Pb + Pb at Coulomb barrier energies. © 1977 The American Physical Society.}, Doi = {10.1103/PhysRevLett.38.592}, Key = {art19} } @article{Soffel:1977yb, Author = {Soffel, M and Müller, B and Greiner, W}, Title = {The electrostatic and gravitational field of spherically symmetric objects}, Journal = {Physics Letters A}, Volume = {62}, Number = {2}, Pages = {67-69}, Year = {1977}, ISSN = {0375-9601}, Abstract = {The electrostatic and gravitational fields of an extended spherically symmetric object is presented. The limit to a point-like object is discussed for Born-Infeld type of electrodynamics and it is shown, that the extreme Reissner-Nordstrøm field, where no event horizon occurs, is unphysical. © 1977.}, Key = {Soffel:1977yb} } @article{Soffel:1977wn, Author = {Soffel, M and Muller, B and Greiner, W}, Title = {Particles in a stationary spherically symmetric gravitational field}, Journal = {Journal of Physics A: Mathematical and General}, Volume = {10}, Number = {4}, Pages = {551-560}, Year = {1977}, ISSN = {0305-4470}, url = {http://dx.doi.org/10.1088/0305-4470/10/4/017}, Abstract = {Dirac's equation has been considered in a Schwarzschild (Reissner-Nordstrom) background. Resonances in a continuum of states are found, similar to the Klein-Gordon case. Also the solutions of the Dirac and Klein-Gordon equations are investigated for an extended gravitating source. Special attention has been given to the case in which the radius of the source tends towards its Schwarzschild radius. A limiting charge-to-mass ratio for black holes is obtained.}, Doi = {10.1088/0305-4470/10/4/017}, Key = {Soffel:1977wn} } @article{art18, Author = {uuml, M and ller, B}, Title = {Positron creation in superheavy quasimolecules}, Journal = {Ann. Rev. Nucl. Science}, Volume = {26}, Pages = {351-383}, Year = {1976}, Key = {art18} } @article{art17, Author = {Betz, W and Soff, G and Müller, B and Greiner, W}, Title = {Direct formation of quasimolecular 1sσ vacancies in uranium-uranium collisions}, Journal = {Physical Review Letters}, Volume = {37}, Number = {16}, Pages = {1046-1049}, Year = {1976}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.37.1046}, Abstract = {The direct (Coulomb) formation of electron vacancies in the 1sσ state of superheavy quasimolecules is investigated for the first time. Its dependence on the impact parameter, projectile energy, and its contribution from excitations into the continum and higher bound states are determined. © 1976 The American Physical Society.}, Doi = {10.1103/PhysRevLett.37.1046}, Key = {art17} } @article{art16, Author = {Gros, M and Muller, B and Greiner, W}, Title = {Radiative transitions induced in heavy-ion collisions}, Journal = {Journal of the Physics B: Atomic and Molecular Physics}, Volume = {9}, Number = {11}, Pages = {1849-1856}, Year = {1976}, ISSN = {0022-3700}, url = {http://dx.doi.org/10.1088/0022-3700/9/11/011}, Abstract = {Amplitudes for radiative transitions in fast-rotating molecules and heavy-ion collisions are derived. The effect of the Coriolis force on the electron motion and on the radiative transition amplitude is formulated. The term in the transition amplitude dependent on the angular velocity reflects the influence of the rotation of the states.}, Doi = {10.1088/0022-3700/9/11/011}, Key = {art16} } @article{art15, Author = {uuml, M and ller, B and Greiner, W}, Title = {The two center Dirac equation}, Journal = {Z. Naturforsch.}, Volume = {31a}, Pages = {1-30}, Year = {1976}, Key = {art15} } @article{Rafelski:1976rf, Author = {Rafelski, J and uuml, M and ller, B}, Title = {Magnetic splitting of quasimolecular electronic states in strong fields}, Journal = {Phys. Rev. Lett.}, Volume = {36}, Pages = {517-520}, Year = {1976}, Key = {Rafelski:1976rf} } @article{Muller:1976ms, Author = {Rafelski, J and Müller, B}, Title = {Vector coupling and bound states of fermions in three space dimensions}, Journal = {Physical Review D: Particles, Fields, Gravitation and Cosmology}, Volume = {14}, Number = {12}, Pages = {3532-3535}, Year = {1976}, ISSN = {0556-2821}, url = {http://dx.doi.org/10.1103/PhysRevD.14.3532}, Abstract = {The behavior of fermions interacting via vector gluons in the strong-coupling limit is investigated. A suitable coupling between the Dirac and the vector-gluon field gives rise to bound-state solutions. The coherent field approximation is employed to find the bound-state masses, which are further discussed by analytical and numerical methods and are found to be positive-definite in the example considered numerically. © 1976 The American Physical Society.}, Doi = {10.1103/PhysRevD.14.3532}, Key = {Muller:1976ms} } @article{Rafelski:1976mu, Author = {Rafelski, J and Müller, B}, Title = {The critical distance in collisions of heavy ions}, Journal = {Physics Letters B}, Volume = {65}, Number = {3}, Pages = {205-208}, Year = {1976}, ISSN = {0370-2693}, Abstract = {There is a large discrepancy in published values of the critical distance in heavy-ion collisions. We have recalculated the critical distance by a more accurate method for symmetric collisions of point nuclei as a function of Z. The reasons for the discrepancy are discussed. © 1976.}, Key = {Rafelski:1976mu} } @article{Muller:1975fh, Author = {Müller, B and Rafelski, J}, Title = {Stabilization of the charged vacuum created by very strong electrical fields in nuclear matter}, Journal = {Physical Review Letters}, Volume = {34}, Number = {6}, Pages = {349-352}, Year = {1975}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.34.349}, Abstract = {The expectation value of electrical charge in charged vacuum is calculated utilizing the Thomas-Fermi model. We find almost complete screening of the nuclear charge. For any given nuclear density there is an upper bound for the electrical potential. For normal nuclear densities this value is - 250 MeV. This suggests that the vacuum is stable against spontaneous formation of heavy, charged particles. © 1975 The American Physical Society.}, Doi = {10.1103/PhysRevLett.34.349}, Key = {Muller:1975fh} } @article{art14, Author = {Smith, RK and Müller, B and Greiner, W and Greenberg, JS and Davis, CK}, Title = {Sudden rearrangements in intermediate molecular systems}, Journal = {Physical Review Letters}, Volume = {34}, Number = {3}, Pages = {117-120}, Year = {1975}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.34.117}, Abstract = {Intensity oscillations are observed in the quasimolecular K x-ray spectrum emitted in high-energy Ni58-Ni58 collisions. The oscillating structure is shown, theoretically, to reflect the existence of a two-step mechanism for the production of molecular-orbital K x rays in which sudden rearrangements of molecular-orbital populations are produced by vibrations between atomic and molecular orbitals of K-hole states during the interpenetration of the electronic clouds. © 1975 The American Physical Society.}, Doi = {10.1103/PhysRevLett.34.117}, Key = {art14} } @article{art12, Author = {Müller, B and Smith, RK and Greiner, W}, Title = {Spectroscopy of superheavy two centre orbitals}, Journal = {Physics Letters B}, Volume = {53}, Number = {5}, Pages = {401-404}, Year = {1975}, ISSN = {0370-2693}, Abstract = {The inner shell molecular orbitals formed in heavy ion collisions become states of superheavy atoms as the two nuclei amalgamate. It is shown that there is a unique correspondence between the scattering energy, i.e., the distance of closest approach, and the shape of the molecular X-ray spectrum of a superheavy system. Thus molecular spectroscopy can be used to investigate the shell structure of superheavy quasimolecules and even, in the limit, of superheavy atoms. © 1975.}, Key = {art12} } @article{art13, Author = {Smith, K and Muller, B and Greiner, W}, Title = {Dynamical theory of intermediate molecular phenomena in heavy ion scattering}, Journal = {Journal of the Physics B: Atomic and Molecular Physics}, Volume = {8}, Number = {1}, Pages = {75-101}, Year = {1975}, ISSN = {0022-3700}, url = {http://dx.doi.org/10.1088/0022-3700/8/1/013}, Abstract = {A general formulation of the collision between two heavy ions is presented. While this formalism may also be applied to nuclear structure problems, the emphasis is placed upon the electronic structure. Molecular and relativistic effects on the electronic motion are incorporated into the formalism through the two-centre-many-body-Dirac equation. The various couplings of the electronic system to the nuclear system are illustrated in two cases. First the relative nuclear motion is treated quantum mechanically and then the semiclassical description of this motion is presented. The formalism is applied to inner shell vacancy production, molecular X-ray transitions and both induced and autoionized positron spectra of the quantum electrodynamics of strong fields. Also induced and spontaneous and induced radiationless transitions are discussed.}, Doi = {10.1088/0022-3700/8/1/013}, Key = {art13} } @article{art09, Author = {Müller, B and Kent-Smith, R and Greiner, W}, Title = {Induced radiative transitions of intermediate molecules in heavy ion collisions}, Journal = {Physics Letters B}, Volume = {49}, Number = {3}, Pages = {219-223}, Year = {1974}, ISSN = {0370-2693}, Abstract = {Three types of transitions exists in intermediate molecules occuring in heavy ion scattering: spontaneous radiative, induced non-radiative, and induced radiative decay. The latter ones yield an asymmetric angular distribution for molecular X-rays with respect to the ion-beam axis. The experimental verification of this effect would furnish an experimentum crucis for both, the existence of molecular X-rays and the induced radiative transitions. © 1974.}, Key = {art09} } @article{art08, Author = {uuml, M and ller, B and Greiner, W}, Title = {The change of the vacuum in superheavy quasimolecules}, Journal = {Phys. Scripta}, Volume = {10A}, Pages = {170-174}, Year = {1974}, Key = {art08} } @article{art07, Author = {Rafelski, J and Müller, B and Soff, G and Greiner, W}, Title = {Critical discussion of the vacuum polarization measurements in muonic atoms}, Journal = {Annals of Physics}, Volume = {88}, Number = {2}, Pages = {419-453}, Year = {1974}, ISSN = {0003-4916}, Abstract = {Recent disagreement between theoretical and experimental values of transition energies for outer states in muonic atoms is discussed in the range of 150-440 keV. A brief review of the present status of calculation of the theoretical contributions is given. A rigorous theoretical framework for the electron-muon system is considered. A set of self-consistent equations is derived. Several mechanisms for the explanation of the discrepancy are discussed. No explanation within the frame of standard quantum electrodynamics is found. © 1974.}, Key = {art07} } @article{art06, Author = {Smith, K and Peitz, H and Müller, B and Greiner, W}, Title = {Induced decay of the neutral vaccum in overcritical fields occurring in heavy-ion collisions}, Journal = {Physical Review Letters}, Volume = {32}, Number = {10}, Pages = {554-556}, Year = {1974}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.32.554}, Abstract = {In critical or nearly critical heavy-ion collisions, induced as well as spontaneous energyless e-e+ pair creation result in the decay of the neutral vacuum. Induced transitions from the negative-energy continuum into a vacant molecular 1s level can occur even in the absence of diving and produce a substantial enhancement and broadening of the previously considered spontaneous positron spectrum. Total cross sections of 5 b have been calculated for U-U collisions. © 1974 The American Physical Society.}, Doi = {10.1103/PhysRevLett.32.554}, Key = {art06} } @article{Rafelski:1974rh, Author = {Rafelski, J and Müller, B and Greiner, W}, Title = {The charged vacuum in over-critical fields}, Journal = {Nuclear Physics B}, Volume = {68}, Number = {2}, Pages = {585-604}, Year = {1974}, ISSN = {0550-3213}, Abstract = {The concept of over-critical fields, i.e. fields in which spontaneous, energy-less electron-position pair creation may occur, is discussed. It is shown that only a charged vacuum can be a stable ground state of the overcritical field. The time-dependent treatment confirms previous results for the cross sections for the auto-ionizing positrons. The questions in connection with the classical Dirac wave functions in over-critical fields are extensively discussed in the frame of the self-consistent formulation of QED including the effects of vacuum polarization and self-energy. © 1974.}, Key = {Rafelski:1974rh} } @article{Soff:1974sp, Author = {Soff, G and uuml, M and ller, B and Rafelski, J}, Title = {Precise values for critical fields in quantum electrodynamics}, Journal = {Z. Naturforsch.}, Volume = {29A}, Pages = {1267-1275}, Year = {1974}, Key = {Soff:1974sp} } @article{art11, Author = {Müller, B and Greiner, W}, Title = {Theory of induced molecular-orbital K X rays in heavy-ion collisions}, Journal = {Physical Review Letters}, Volume = {33}, Number = {8}, Pages = {469-473}, Year = {1974}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.33.469}, Abstract = {The mechanisms of spontaneous and induced emission of radiation are derived from the Dirac equation in a rotating coordinate system. The molecular-orbital x-ray spectra exhibit a strong asymmetry with respect to the beam axis. The asymmetry peaks for the high-energy transitions, which can be used for spectroscopy of two-center orbitals. © 1974 The American Physical Society.}, Doi = {10.1103/PhysRevLett.33.469}, Key = {art11} } @article{art10, Author = {Soff, G and Müller, B}, Title = {Transition energies in the ionized Br+Br quasi-molecule}, Journal = {Lettere al Nuovo Cimento Series 2}, Volume = {9}, Number = {14}, Pages = {557-560}, Year = {1974}, ISSN = {0375-930X}, url = {http://dx.doi.org/10.1007/BF02759371}, Doi = {10.1007/BF02759371}, Key = {art10} } @article{fds318460, Author = {Rafelski, J and Mueller, B and Greiner, W}, Title = {The charged vacuum in overcritical fields}, Journal = {NUKLEONIKA}, Volume = {19}, Number = {7-8}, Pages = {747-765}, Year = {1974}, Key = {fds318460} } @article{Muller:1973ya, Author = {Müller, B and Rafelski, J and Greiner, W}, Title = {Solution of the Dirac equation with two Coulomb centres}, Journal = {Physics Letters B}, Volume = {47}, Number = {1}, Pages = {5-7}, Year = {1973}, ISSN = {0370-2693}, url = {http://dx.doi.org/10.1016/0370-2693(73)90554-6}, Abstract = {The Dirac equation for a relativistic particle (electron) in the field of two Coulomb centres Z1 and Z2 - pointlike as well as extended charges - has been solved. The systems BrBr, IAu, UU are shown as examples. © 1973.}, Doi = {10.1016/0370-2693(73)90554-6}, Key = {Muller:1973ya} } @article{art05, Author = {Müller, B and Rafelski, J and Greiner, W}, Title = {Electron wave functions in over-critical electrostatic potentials}, Journal = {Il Nuovo Cimento A Series 10}, Volume = {18}, Number = {3}, Pages = {551-573}, Year = {1973}, ISSN = {0369-3546}, url = {http://dx.doi.org/10.1007/BF02722798}, Abstract = {The mathematical properties of the solutions of the Dirac equation in over-critical external potentials are investigated. The 1/r Coulomb potential is treated as the limit R → 0 of cut-off Coulomb potentials (R is the cut-off parameter). The results are interpreted in terms of quantum electrodynamics. A number of new physical phenomena occur in quantum electrodynamics of strong fields. One of the most interesting ones is the autoionization of positrons (energyless creation of electron-positron pairs) in over-critical external fields. © 1973 Società Italiana di Fisica.}, Doi = {10.1007/BF02722798}, Key = {art05} } @article{art04, Author = {Soff, G and uuml, M and ller, B and Rafelski, J and Greiner, W}, Title = {Solution of the Dirac equation for scalar potentials and its implications in atomic physics}, Journal = {Z. Naturforsch.}, Volume = {28a}, Pages = {1389-1396}, Year = {1973}, Key = {art04} } @article{art03, Author = {Peitz, H and Müller, B and Rafelski, J and Greiner, W}, Title = {Autoionization spectra of positrons in heavy-ion collisions}, Journal = {Lettere al Nuovo Cimento Series 2}, Volume = {8}, Number = {1}, Pages = {37-42}, Year = {1973}, ISSN = {0375-930X}, url = {http://dx.doi.org/10.1007/BF02727627}, Doi = {10.1007/BF02727627}, Key = {art03} } @article{art02, Author = {Müller, B and Rafelski, J and Greiner, W}, Title = {Auto-ionization of positrons in heavy ion collisions}, Journal = {The European Physical Journal A - Hadrons and Nuclei}, Volume = {257}, Number = {3}, Pages = {183-211}, Year = {1972}, ISSN = {1434-6001}, url = {http://dx.doi.org/10.1007/BF01401203}, Abstract = {Autoionization of positrons occurs as a fundamentally new process of quantum electrodynamics, if empty 1 s- or 2 p1/2- etc. electronic shells obtain binding energies larger than 2 mec2. This effect should be experimentally observable in the scattering of very heavy ions (Z≧80) on each other since in such collisions superheavy electronic molecules are formed (superheavy quasi-molecules). The scattering mechanism and the distribution of autoionization positrons are discussed. The adiabaticity of the heavy ion collision is studied and the electron-positron pair production background to the ionization problem is estimated. Analytic solutions are obtained for 1/r-potentials for the case Zα≧1. The phase shifts of negative energy solutions in the case of cutoff Coulomb potentials reveal the accuracy of the autoionization formalism. © 1972 Springer-Verlag.}, Doi = {10.1007/BF01401203}, Key = {art02} } @article{art01, Author = {Rafelski, J and Müller, B and Greiner, W}, Title = {Superheavy electronic molecules}, Journal = {Lettere al Nuovo Cimento Series 2}, Volume = {4}, Number = {11}, Pages = {469-474}, Year = {1972}, ISSN = {0375-930X}, url = {http://dx.doi.org/10.1007/BF02757147}, Doi = {10.1007/BF02757147}, Key = {art01} } @article{Peitz:1972zz, Author = {Müller, B and Peitz, H and Rafelski, J and Greiner, W}, Title = {Solution of the dirac equation for strong external fields}, Journal = {Physical Review Letters}, Volume = {28}, Number = {19}, Pages = {1235-1238}, Year = {1972}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.28.1235}, Abstract = {The 1s bound state of superheavy atoms and molecules reaches a binding energy of -2mc2 at 169. It is shown that the K shell is still localized in r space even beyond this critical proton number and that it has a width Γ (several keV large) which is a positron escape width for ionized K shells. The suggestion is made that this effect can be observed in the collision of very heavy ions (superheavy molecules) during the collision. © 1972 The American Physical Society.}, Doi = {10.1103/PhysRevLett.28.1235}, Key = {Peitz:1972zz} } @article{Muller:1972ab, Author = {uuml, M and ller, B and Rafelski, J and Greiner, W}, Title = {Electron shells in strong external fields}, Journal = {Z. Phys. A}, Volume = {257}, Number = {1}, Pages = {62-77}, Year = {1972}, ISSN = {1434-6001}, url = {http://dx.doi.org/10.1007/BF01398198}, Abstract = {When the charge of a nucleus exceeds Z=Zcrâ‰ˆ 164-172 the energy of the 1 s-electron level is lowered beyond the critical value of -mec2. Then this bound level is degenerated with negative energy continuum solutions of the Dirac equation and becomes a resonance, whose shape varies and is approximately of Breit-Wigner type for Z-Zcrâ‰³5. The physical meaning of this resonance can be understood most easily if the 1 s-level is unoccupied (K-hole). In this case a positron may escape if Z>Zcr, a process, that can be interpreted as auto-ionization of the positron. This fundamentally new process of quantum electrodynamics of strong fields can be tested experimentally by scattering very heavy ions (Zâ‰§80) on each other since in such collisions superheavy electronic molecules occur (superheavy quasimolecules). Â© 1972 Springer-Verlag.}, Doi = {10.1007/BF01398198}, Key = {Muller:1972ab} } @article{fds304599, Author = {Müller, B and Rafelski, J and Greiner, W}, Title = {Electron shells in over-critical external fields}, Journal = {The European Physical Journal A - Hadrons and Nuclei}, Volume = {257}, Number = {1}, Pages = {62-77}, Year = {1972}, ISSN = {1434-6001}, url = {http://dx.doi.org/10.1007/BF01398198}, Abstract = {When the charge of a nucleus exceeds Z=Zcr≈ 164-172 the energy of the 1 s-electron level is lowered beyond the critical value of -mec2. Then this bound level is degenerated with negative energy continuum solutions of the Dirac equation and becomes a resonance, whose shape varies and is approximately of Breit-Wigner type for Z-Zcr≳5. The physical meaning of this resonance can be understood most easily if the 1 s-level is unoccupied (K-hole). In this case a positron may escape if Z>Zcr, a process, that can be interpreted as auto-ionization of the positron. This fundamentally new process of quantum electrodynamics of strong fields can be tested experimentally by scattering very heavy ions (Z≧80) on each other since in such collisions superheavy electronic molecules occur (superheavy quasimolecules). © 1972 Springer-Verlag.}, Doi = {10.1007/BF01398198}, Key = {fds304599} } %% Papers Submitted @article{fds226030, Author = {Müller, B.}, Title = {A New Phase of Matter: Quark-Gluon Plasma Beyond the Hagedorn Critical Temperature}, Booktitle = {Melting Hadrons, Boiling Quarks}, Publisher = {Springer}, Editor = {Rolf Hagedorn and Johann Rafelski}, Year = {2015}, url = {http://arxiv.org/pdf/1501.06077}, Abstract = {http://arxiv.org/abs/1501.06077}, Key = {fds226030} } @article{fds225720, Author = {Monnai, A. and Müller, B.}, Title = {Collinear parton splitting in early thermalization and chemical equilibration}, Year = {2014}, url = {http://arxiv.org/pdf/1403.7310.pdf}, Abstract = {http://arxiv.org/abs/arXiv:1403.7310}, Key = {fds225720} } @article{fds211280, Author = {Coleman-Smith, C.E. and Müller, B.}, Title = {Constituent mass dependence of transport coefficients in a quark-gluon plasma}, Year = {2012}, url = {http://arxiv.org/pdf/1209.3328}, Abstract = {http://arxiv.org/abs/1209.3328}, Key = {fds211280} } %% Preprints @article{fds201480, Author = {Foster, J.G. and Müller, B}, Title = {Physics with two time dimensions}, Year = {2010}, url = {http://arxiv.org/pdf/1001.2485}, Abstract = {http://arxiv.org/abs/1001.2485}, Key = {fds201480} } @article{fds21287, Author = {Biro, T.S. and Müller, B.}, Title = {Chaotic quantization of four-dimensional U(1) lattice gauge theory}, Year = {2003}, url = {http://arxiv.org/pdf/hep-lat/0307028}, Abstract = {http://arxiv.org/abs/hep-lat/0307028}, Key = {fds21287} } @article{fds21288, Author = {Müller, B. and Schäfer, A.}, Title = {Entropy production in high energy processes}, Year = {2003}, url = {http://arxiv.org/pdf/hep-ph/0306309}, Abstract = {http://arxiv.org/abs/hep-ph/0306309}, Key = {fds21288} } %% Other @misc{fds138723, Author = {Jacobs, P. and Kharzeev, D. and Müller, B. and Nagle, J. and Rajagopal, K. and Vigdor, S.}, Title = {Phases of QCD: Summary of the Rutgers long range plan town meeting, January 12-14, 2007}, Year = {2007}, Month = {January}, url = {http://arXiv.org/pdf/0705.1930}, Abstract = {http://arXiv.org/abs/0705.1930}, Key = {fds138723} } @misc{fds14816, Author = {Carlson, J. and Holstein, B. and Ji, X.D. and McLaughlin, G. and Müller, B. and Nazarewicz, W. and Rajagopal, K. and Roberts, W. and Wang, X.N.}, Title = {A vision for nuclear theory}, Year = {2003}, Month = {November}, url = {http://arxiv.org/pdf/nucl-th/0311056}, Abstract = {This is the report of the NSAC Subcommittee on Nuclear Theory in response to a charge by the funding agencies to review and evaluate current NSF and DOE supported efforts in nuclear theory and identify strategic plans to ensure a strong U.S. nuclear theory program under various funding scenarios.}, Key = {fds14816} }