## Publications of Thomas C. Mehen    :chronological  alphabetical  combined listing:

%% Papers Published
@article{fds331487,
Author = {Hornig, A and Kang, D and Makris, Y and Mehen, T},
Title = {Transverse vetoes with rapidity cutoff in
SCET},
Journal = {Journal of High Energy Physics},
Volume = {2017},
Number = {12},
Year = {2017},
Month = {December},
url = {http://dx.doi.org/10.1007/JHEP12(2017)043},
Abstract = {© 2017, The Author(s). We consider di-jet production in
hadron collisions where a transverse veto is imposed on
radiation for (pseudo-)rapidities in the central region
only, where this central region is defined with rapidity
cutoff. For the case where the transverse measurement (e.g.,
transverse energy or min p T for jet veto) is parametrically
larger relative to the typical transverse momentum beyond
the cutoff, the cross section is insensitive to the cutoff
parameter and is factorized in terms of collinear and soft
degrees of freedom. The virtuality for these degrees of
freedom is set by the transverse measurement, as in typical
transverse-momentum dependent observables such as Drell-Yan,
Higgs production, and the event shape broadening. This paper
focuses on the other region, where the typical transverse
momentum below and beyond the cutoff is of similar size. In
this region the rapidity cutoff further resolves soft
different rapidities but identical virtuality. This gives
rise to rapidity logarithms of the rapidity cutoff parameter
which we resum using renormalization group methods. We
factorize the cross section in this region in terms of soft
and collinear functions in the framework of soft-collinear
effective theory, then further refactorize the soft function
as a convolution of the (u)soft and soft-collinear
functions. All these functions are calculated at one-loop
order. As an example, we calculate a differential cross
section for a specific partonic channel, qq ′ → qq ′ ,
for the jet shape angularities and show that the
refactorization allows us to resum the rapidity logarithms
and significantly reduce theoretical uncertainties in the
jet shape spectrum.},
Doi = {10.1007/JHEP12(2017)043},
Key = {fds331487}
}

@article{fds331488,
Author = {Mehen, T},
Title = {Implications of heavy quark-diquark symmetry for excited
doubly heavy baryons and tetraquarks},
Journal = {Physical Review D},
Volume = {96},
Number = {9},
Year = {2017},
Month = {November},
url = {http://dx.doi.org/10.1103/PhysRevD.96.094028},
Abstract = {© 2017 American Physical Society. We give heavy
quark-diquark symmetry predictions for doubly heavy baryons
and tetraquarks in light of the recent discovery of the
Ξcc++ by LHCb. For five excited doubly charm baryons that
are predicted to lie below the ΛcD threshold, we give
predictions for their electromagnetic and strong decays
using a previously developed chiral Lagrangian with heavy
quark-diquark symmetry. Based on the mass of the Ξcc++, the
existence of a doubly heavy bottom I=0 tetraquark that is
stable to strong and electromagnetic decays has been
predicted. If the mass of this state is below 10405 MeV, as
predicted in some models, we argue using heavy quark-diquark
symmetry that the JP=1+ I=1 doubly bottom tetraquark state
will lie just below the open bottom threshold and likely be
a narrow state as well. In this scenario, we compute strong
decay width for this state using a new Lagrangian for doubly
heavy tetraquarks which is related to the singly heavy
baryon Lagrangian by heavy quark-diquark
symmetry.},
Doi = {10.1103/PhysRevD.96.094028},
Key = {fds331488}
}

@article{fds328273,
Author = {Bain, R and Makris, Y and Mehen, T and Dai, L and Leibovich,
AK},
Title = {NRQCD Confronts LHCb Data on Quarkonium Production within
Jets.},
Journal = {Physical Review Letters},
Volume = {119},
Number = {3},
Pages = {032002},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1103/physrevlett.119.032002},
Abstract = {We analyze the recent LHCb measurement of the distribution
of the fraction of the transverse momentum, z(J/ψ), carried
by the J/ψ within a jet. LHCb data are compared with
analytic calculations using the fragmenting jet function
(FJF) formalism for studying J/ψ in jets. Logarithms in the
FJFs are resummed using Dokshitzer-Gribov-Lipatov-Altarelli-Parisi
evolution. We also convolve hard QCD partonic cross
sections, showered with pythia, with leading order
nonrelativistic quantum chromodynamics (NRQCD) fragmentation
functions and obtain consistent results. Both approaches use
madgraph to calculate the hard process that creates the jet
initiating parton. These calculations give reasonable
agreement with the z(J/ψ) distribution that was shown to be
poorly described by default pythia simulations in the LHCb
paper. We compare our predictions for the J/ψ distribution
using various extractions of nonperturbative NRQCD
long-distance matrix elements (LDMEs) in the literature.
NRQCD calculations agree with LHCb data better than default
pythia regardless of which fit to the LDMEs is used. LDMEs
from fits that focus exclusively on high transverse momentum
data from colliders are in good agreement with the LHCb
measurement.},
Doi = {10.1103/physrevlett.119.032002},
Key = {fds328273}
}

@article{fds327375,
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 = {fds327375}
}

@article{fds322008,
Author = {Bain, R and Makris, Y and Mehen, T},
Title = {Transverse momentum dependent fragmenting jet functions with
applications to quarkonium production},
Journal = {The Journal of High Energy Physics},
Volume = {2016},
Number = {11},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1007/JHEP11(2016)144},
Doi = {10.1007/JHEP11(2016)144},
Key = {fds322008}
}

@article{fds322009,
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 = {fds322009}
}

@article{fds322010,
Author = {Bain, R and Dai, L and Hornig, A and Leibovich, AK and Makris, Y and Mehen,
T},
Title = {Analytic and Monte Carlo studies of jets with heavy mesons
and quarkonia},
Journal = {The Journal of High Energy Physics},
Volume = {2016},
Number = {6},
Year = {2016},
Month = {June},
url = {http://dx.doi.org/10.1007/JHEP06(2016)121},
Doi = {10.1007/JHEP06(2016)121},
Key = {fds322010}
}

@article{fds322011,
Author = {Hornig, A and Makris, Y and Mehen, T},
Title = {Jet shapes in dijet events at the LHC in
SCET},
Journal = {The Journal of High Energy Physics},
Volume = {2016},
Number = {4},
Pages = {1-41},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1007/JHEP04(2016)097},
Doi = {10.1007/JHEP04(2016)097},
Key = {fds322011}
}

@article{fds287615,
Author = {Mehen, T},
Title = {Hadronic loops versus factorization in effective field
theory calculations of},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {92},
Number = {3},
Year = {2015},
Month = {August},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.92.034019},
Doi = {10.1103/PhysRevD.92.034019},
Key = {fds287615}
}

@article{fds322012,
Author = {Mehen, T},
Title = {New tests of NRQCD from Quarkonia within
jets},
Journal = {PoS - Proceedings of Science},
Volume = {26-30-May-2015},
Year = {2015},
Month = {January},
Abstract = {I review the current status of quarkonium production theory
based on the non-relativistic QCD factorization formalism
(NRQCD). While this theory describes much of the world's
data on J=y and ¡ production, there are still outstanding
problems, most notably the polarization of quarkonia at
large pT in hadron colliders. In this talk we will present
new tests of NRQCD involving the distribution of quarkonia
within jets. The distribution of hadrons within jets is
determined by nonperturbative functions called fragmenting
jet functions (FJFs). FJFs are convolutions of fragmentation
functions, evolved to the jet energy scale, with
perturbatively calculable matching coefficients. I show how
the FJFs for quarkonia can be calculated in NRQCD in terms
of a few NRQCD long-distance matrix elements (LDME), so the
dependence of the cross section on the energy fraction of
the heavy quarkonium, z, is sensitive to the underlying
production mechanism, and therefore provides a new test of
NRQCD. The jet energy and z dependence of the cross section
can be used to perform an independent extraction of NRQCD
LDME. Finally, I describe ongoing work building on this
result. This includes comparison of analytic resummed
calculations with Monte Carlo simulations for two-jet events
in e + e - collisions with B mesons, and three-jet events
with J=y, as well as the definition of boost invariant jet
substructure variables and calculation of a boost invariant
soft function that are necessary for analytic calculations
of jet cross sections at the Large Hadron Collider.
QCD.},
Key = {fds322012}
}

@article{fds287614,
Author = {Baumgart, M and Leibovich, AK and Mehen, T and Rothstein,
IZ},
Title = {Probing quarkonium production mechanisms with jet
substructure},
Journal = {The Journal of High Energy Physics},
Volume = {2014},
Number = {11},
Year = {2014},
Month = {November},
url = {http://arxiv.org/abs/arXiv:1406.2295},
Doi = {10.1007/JHEP11(2014)003},
Key = {fds287614}
}

@article{fds287618,
Author = {Kim, C and Idilbi, A and Mehen, T and Yoon, YW},
Title = {Production of stoponium at the LHC},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {89},
Number = {7},
Year = {2014},
Month = {April},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/arXiv:1401.1284},
Doi = {10.1103/PhysRevD.89.075010},
Key = {fds287618}
}

@article{fds221123,
Author = {Thomas Mehen and Joshua W. Powell},
Title = {Line shapes in Υ(5S)→B(∗) B(∗)π
with Z(10610) and Z(10650) using effective field
theory},
Journal = {Phys. Rev. D88:034017},
Year = {2013},
url = {http://arxiv.org/abs/1306.5459},
Key = {fds221123}
}

@article{fds287621,
Author = {Mehen, T and Powell, JW},
Title = {Line shapes in Υ(5S)→B(*)B
̄(*)π with Z(10610) and Z(10650)
using effective field theory},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {88},
Number = {3},
Year = {2013},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.88.034017},
Abstract = {The Belle Collaboration recently discovered two resonances,
Z b(10610) and Zb(10650) - denoted Zb and Zb′ - in the
decays Υ(5S)→Υ(nS)π+π - for n=1, 2, or 3, and
Υ(5S)→hb(mP) π+π- for m=1 or 2. These resonances lie
very close to the B*B̄ and B*B̄* thresholds, respectively.
A recent Belle analysis of the three-body decays
Υ(5S)→[B(*)B̄( *)]â̂π± gives further evidence for
the existence of these states. In this paper we analyze this
decay using an effective theory of B mesons interacting via
strong short-range interactions. Some parameters in this
theory are constrained using existing data on
Υ(5S)→B(*)B̄( *) decays, which requires the inclusion of
heavy quark spin symmetry violating operators. We then
calculate the differential distribution for
Υ(5S)→B(*)B̄(*) π as a function of the invariant mass
of the B(*)B ̄(*) pair, obtaining qualitative agreement
with experimental data. We also calculate angular
distributions in the decay Υ(5S)→Zb(′)π which are
sensitive to the molecular character of the Zb(′). © 2013
American Physical Society.},
Doi = {10.1103/PhysRevD.88.034017},
Key = {fds287621}
}

@article{fds287622,
Author = {Fleming, S and Leibovich, AK and Mehen, T and Rothstein,
IZ},
Title = {Anomalous dimensions of the double parton fragmentation
functions},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {87},
Number = {7},
Year = {2013},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/arXiv:1301.3822},
Abstract = {Double parton fragmentation is a process in which a pair of
partons produced in the short-distance process hadronize
into the final state hadron. This process is important for
quarkonium production when the transverse momentum is much
greater than the quark mass. Resummation of logarithms of
the ratio of these two scales requires the evolution
equations for double parton fragmentation functions (DPFF).
In this paper we complete the one-loop evaluation of the
anomalous dimensions for the DPFF. We also consider possible
mixing between the DPFF and single parton power suppressed
gluon fragmentation and show that such effects are
Doi = {10.1103/PhysRevD.87.074022},
Key = {fds287622}
}

@article{fds287643,
Author = {Mehen, T and Yang, D-L},
Title = {The role of charmed meson loops in charmonium
decays},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {85},
Number = {1},
Year = {2012},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.85.014002},
Abstract = {We investigate the effect of intermediate charmed meson
loops on the M1 radiative decays J/ψ→η cγ and ψ
′→ηc(′)γ as well as the isospin [SU(3)] violating
chiral perturbation theory. The calculations include tree
level as well as one loop diagrams and are compared to the
latest data from CLEO and BES-III. Our fit constrains the
couplings of 1S and 2S charmonium multiplets to charmed
mesons, denoted g 2 and g2′, respectively. We find that
there are two sets of solutions for g 2 and g2′. One set,
which agrees with previous values of the product g 2g2′
extracted from analyses that consider only loop
contributions to ψ ′→ J/ψπ0(η), can only fit data on
radiative decays with fine-tuned cancellations between tree
level diagrams and loops in that process. The other solution
for g 2 and g2′ leads to couplings that are smaller by a
factor of 2.3. In this case tree level and loop
contributions are of comparable size and the numerical
values of the tree level contributions to radiative decays
are consistent with estimates based on the quark model as
well as nonrelativistic QCD. This result shows that tree
level heavy hadron chiral perturbation theory couplings are
as important as the one loop graphs with charmed mesons in
these charmonium decays. The couplings g 2 and g2′ are
also important for the calculations of the decays of charmed
meson bound states, such as the X(3872), to conventional
charmonia. © 2012 American Physical Society.},
Doi = {10.1103/PhysRevD.85.014002},
Key = {fds287643}
}

@article{fds287645,
Author = {Fleming, S and Mehen, T},
Title = {Decay of the X(3872) into χ cJ and the operator
product expansion in effective field theory},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {85},
Number = {1},
Year = {2012},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.85.014016},
Abstract = {We consider a low-energy effective theory for the X(3872)
(XEFT) that can be used to systematically analyze the decay
and production of the X(3872) meson, assuming that it is a
weakly bound state of charmed mesons. In a previous paper,
we calculated the decays of X(3872) into χ cJ plus pions
using a two-step procedure in which Heavy Hadron Chiral
Perturbation Theory (HHχPT) amplitudes are matched onto
XEFT operators and then X(3872) decay rates are calculated
using these operators. The procedure leads to IR divergences
in the three-body decay X(3872)→χ cJππ when virtual D
mesons can go on shell in tree level HHχPT diagrams. In
previous work, we regulated these IR divergences with the D
*0 width. In this work, we carefully analyze X(3872)→χ
cJπ0 and X(3872)→χ cJππ using the operator product
expansion in XEFT. Forward scattering amplitudes in HHχPT
are matched onto local operators in XEFT, the imaginary
parts of which are responsible for the decay of the X(3872).
Here we show that the IR divergences are regulated by the
binding momentum of the X(3872) rather than the width of the
D *0 meson. In the operator product expansion, these IR
divergences cancel in the calculation of the matching
coefficients so the correct predictions for the X(3872)→χ
c1ππ do not receive enhancements due to the width of the D
*0. We give updated predictions for the decay X(3872)→χ
Society.},
Doi = {10.1103/PhysRevD.85.014016},
Key = {fds287645}
}

@article{fds287646,
Author = {Fleming, S and Leibovich, AK and Mehen, T and Rothstein,
IZ},
Title = {Systematics of quarkonium production at the LHC and double
parton fragmentation},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {86},
Number = {9},
Year = {2012},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/1301.3822},
Abstract = {In this paper, we discuss the systematics of quarkonium
production at the LHC. In particular, we focus on the
necessity to sum logs of the form log(Q/p ≥) and log(p
≥/m Q). We show that the former contributions are power
suppressed, while the latter, whose contribution in
fragmentation is well known, also arise in the short
distance (i.e., nonfragmentation) production mechanisms.
Though these contributions are suppressed by powers of m Q/p
≥, they can be enhanced by inverse powers of v, the
relative velocity between heavy quarks in the quarkonium. In
the limit p ≥m Q, short-distance production can be thought
of as the fragmentation of a pair of partons (i.e., the
heavy quark and antiquark) into the final state quarkonium.
We derive an all-order factorization theorem for this
process in terms of double parton fragmentation functions
and calculate the one-loop anomalous dimension matrix for
the double parton fragmentation functions. © 2012 American
Physical Society.},
Doi = {10.1103/PhysRevD.86.094012},
Key = {fds287646}
}

@article{fds287647,
Author = {Mehen, T and Yang, D-L},
Title = {On the Role of Charmed Meson Loops in Charmonium
Decays},
Journal = {Phys.Rev. D85:014002},
Year = {2012},
url = {http://arxiv.org/abs/1111.3884},
Key = {fds287647}
}

@article{fds287648,
Author = {Fleming, S and Mehen, T},
Title = {The decay of the X(3872) into &chicJ and the Operator
Product Expansion in XEFT},
Journal = {Phys.Rev. D85:014016},
Year = {2012},
url = {http://arxiv.org/abs/1110.0265},
Key = {fds287648}
}

@article{fds287644,
Author = {Mehen, T and Powell, JW},
Title = {Heavy quark symmetry predictions for weakly bound B-meson
molecules},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {84},
Number = {11},
Year = {2011},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/1109.3479},
Abstract = {Recently the Belle collaboration discovered two resonances,
Z b(10610) and Z b(10650), that lie very close to the BB ̄*
and B *B ̄* thresholds, respectively. It is natural to
suppose that these are molecular states of bottom and
antibottom mesons. Under this assumption, we introduce an
effective field theory for the Z b(10610) and Z b(10650), as
well as similar unobserved states that are expected on the
basis of heavy quark spin symmetry. The molecules are
assumed to arise from short-range interactions that respect
heavy quark spin symmetry. We use the theory to calculate
line shapes in the vicinity of B( *)B ̄(*) thresholds as
well as two-body decay rates of the new bottom meson bound
states. We derive new heavy quark spin symmetry predictions
for the parameters appearing in the line shapes as well as
the total and partial widths of the states. © 2011 American
Physical Society.},
Doi = {10.1103/PhysRevD.84.114013},
Key = {fds287644}
}

@article{fds287649,
Author = {Mehen, T and Springer, R},
Title = {Radiative Decays of X(3872) &rarr &psi(2S) &gamma and
&psi(4040) &rarr X(3872) &gamma in Effective Field
Theory},
Journal = {Phys.Rev.D83:094009},
Volume = {83},
Number = {9},
Year = {2011},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/1101.5175},
Abstract = {Heavy hadron chiral perturbation theory (HHÏ‡PT) and XEFT
are applied to the decays X(3872)â†’Ïˆ(2S)Î³ and
Ïˆ(4040)â†’X(3872)Î³ under the assumption that the
X(3872) is a molecular bound state of neutral charm mesons.
In these decays the emitted photon energies are 181MeV and
165MeV, respectively, so HHÏ‡PT can be used to calculate
the underlying D0D Ì„0*+DÌ„0D0 *â†’Ïˆ(2S)Î³
or Ïˆ(4040)â†’(D0D Ì„0*+DÌ„0D0*) Î³
transition. These amplitudes are matched onto XEFT to obtain
decay rates. The decays receive contributions from both
long-distance and short-distance processes. We study the
polarization of the Ïˆ(2S) in the decay
X(3872)â†’Ïˆ(2S)Î³ and the angular distribution of
X(3872) in the decay Ïˆ(4040)â†’X(3872)Î³ and find
they can be used to differentiate between different decay
mechanisms as well as discriminate between 2-+ and 1++
quantum number assignments of the X(3872). Â© 2011
American Physical Society.},
Doi = {10.1103/PhysRevD.83.094009},
Key = {fds287649}
}

@article{fds305720,
Author = {Mehen, T and Springer, R},
Title = {Radiative decays X(3872)→ψ(2S)γ and ψ(4040)→X(3872)
γ in effective field theory},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {83},
Number = {9},
Year = {2011},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.83.094009},
Abstract = {Heavy hadron chiral perturbation theory (HHχPT) and XEFT
are applied to the decays X(3872)→ψ(2S)γ and
ψ(4040)→X(3872)γ under the assumption that the X(3872)
is a molecular bound state of neutral charm mesons. In these
decays the emitted photon energies are 181MeV and 165MeV,
respectively, so HHχPT can be used to calculate the
underlying D0D ̄0*+D̄0D0 *→ψ(2S)γ or ψ(4040)→(D0D
̄0*+D̄0D0*) γ transition. These amplitudes are matched
onto XEFT to obtain decay rates. The decays receive
contributions from both long-distance and short-distance
processes. We study the polarization of the ψ(2S) in the
decay X(3872)→ψ(2S)γ and the angular distribution of
X(3872) in the decay ψ(4040)→X(3872)γ and find they can
be used to differentiate between different decay mechanisms
as well as discriminate between 2-+ and 1++ quantum number
assignments of the X(3872). © 2011 American Physical
Society.},
Doi = {10.1103/PhysRevD.83.094009},
Key = {fds305720}
}

@article{fds287650,
Author = {Idilbi, A and Kim, C and Mehen, T},
Title = {Pair production of color-octet scalars at the
LHC},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {82},
Number = {7},
Year = {2010},
ISSN = {1550-7998},
url = {http://hdl.handle.net/10161/4280 Duke open
access},
Abstract = {Heavy colored scalar particles, which exist in many models
of new physics, can be pair produced at the LHC via
gluon-gluon fusion and possibly form quarkoniumlike bound
states. If the scalars are also charged under the
electroweak gauge group, these bound states can then decay
into electroweak bosons. This yields a resonant cross
section for final states such as γγ that can exceed
standard model backgrounds. This paper studies this process
in the Manohar-Wise model of color-octet scalars (COS).
Important threshold logarithms and final state Coulomb-like
QCD interactions are resummed using effective field theory.
We compute the resummed cross section for gluon-gluon fusion
to COS pairs at the LHC as well as the resonant cross
section for octetonium decaying to γγ. The latter cross
section exceeds the standard model diphoton cross section
when the COS mass is less than 500 (350) GeV for
√s=14(7)TeV. Nonobservation of resonances below these
energies can significantly improve existing bounds on COS
masses. © 2010 The American Physical Society.},
Doi = {10.1103/PhysRevD.82.075017},
Key = {fds287650}
}

@article{fds287651,
Author = {Braaten, E and Hammer, H-W and Mehen, T},
Title = {Scattering of an ultrasoft pion and the X(3872)},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {82},
Number = {3},
Year = {2010},
ISSN = {1550-7998},
url = {http://hdl.handle.net/10161/4278 Duke open
access},
Abstract = {The identification of the X(3872) as a loosely-bound
charm-meson molecule allows it to be described by an
effective field theory, called XEFT, for the D*D̄, DD̄*,
and DD̄π sector of QCD at energies small compared to the
pion mass. We point out that this effective field theory can
be extended to the sector that includes an additional pion
and used to calculate cross sections for the scattering of a
pion and the X(3872). If the collision energy is much
smaller than the pion mass, the cross sections are
completely calculable at leading order in terms of the
masses and widths of the charm mesons, pion masses, and the
binding energy of the X(3872). We carry out an explicit
calculation of the cross section for the breakup of the
X(3872) into D*+D̄*0 by the scattering of a very low energy
π+. ©2010 The American Physical Society.},
Doi = {10.1103/PhysRevD.82.034018},
Key = {fds287651}
}

@article{fds287652,
Author = {Idilbi, A and Kim, C and Mehen, T},
Title = {Factorization and resummation for single color-octet scalar
production at the LHC},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {79},
Number = {11},
Year = {2009},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/0903.3668},
Abstract = {Heavy colored scalar particles appear in a variety of new
physics (NP) models and could be produced at the Large
Hadron Collider. Knowing the total production cross section
is important for searching for these states and establishing
bounds on their masses and couplings. Using soft-collinear
effective theory, we derive a factorization theorem for the
process pp→SX, where S is a color-octet scalar, that is
applicable to any NP model provided the dominant production
mechanism is gluon-gluon fusion. The factorized result for
the inclusive cross section is similar to that for the
standard model Higgs production; however, differences arise
due to color exchange between initial and final states. We
provide formulas for the total cross section with large
(partonic) threshold logarithms resummed to next-to-leading
logarithm accuracy. The resulting K factors are similar to
those found in Higgs production. We apply our formalism to
the Manohar-Wise model and find that the next-to-leading
logarithm cross section is roughly 2 times (3 times) as
large as the leading order cross section for a color-octet
scalar of mass of 500 GeV (3 TeV). A similar enhancement
should appear in any NP model with color-octet scalars. ©
2009 The American Physical Society.},
Doi = {10.1103/PhysRevD.79.114016},
Key = {fds287652}
}

@article{fds287653,
Author = {Kim, C and Mehen, T},
Title = {Color octet scalar bound states at the LHC},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {79},
Number = {3},
Year = {2009},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/0903.3668},
Abstract = {One possible extension of the standard model scalar sector
includes SU(2)L doublet scalars that are color octets rather
than singlets. We focus on models in which the couplings to
fermions are consistent with the principle of minimal flavor
violation, in which case these color-octet scalars couple
most strongly to the third generation of quarks. When the
Yukawa coupling of color-octet scalars to standard model
fermions is less than unity, these states can live long
enough to bind into color-singlet spin-0 hadrons, which we
call octetonia. In this paper, we consider the phenomenology
of octetonia at the Large Hadron Collider. Predictions for
their production via gluon-gluon fusion and their two-body
decays into standard model gauge bosons, Higgs bosons, and
t̄t are presented. © 2009 The American Physical
Society.},
Doi = {10.1103/PhysRevD.79.035011},
Key = {fds287653}
}

@article{fds152772,
Author = {Thomas Mehen},
Title = {On non-relativistic conformal field theory and trapped
atoms: Virial theorems and the state-operator correspondence
in three dimensions},
Journal = {Phys. Rev. A 78, 013614},
Year = {2008},
url = {http://arXiv.org/abs/0712.0867},
Abstract = {The field theory of nonrelativistic fermions interacting via
contact interactions can be used to calculate the properties
of few-body systems of cold atoms confined in harmonic
traps. The state-operator correspondence of Non-Relativistic
Conformal Field Theory (NRCFT) shows that the energy
eigenvalues (in oscillator units) of N harmonically trapped
fermions can be calculated from the scaling dimensions of
N-fermion operators in the NRCFT. They are also in
one-to-one correspondence with zero-energy, scale-invariant
solutions to the N-body problem in free space. We show that
these two mappings of the trapped fermion problem to free
space problems are related by an automorphism of the SL(2,R)
algebra of the conformal symmetry of fermions at the unitary
limit. This automorphism exchanges the internal Hamiltonian
of the gas with the trapping potential and hence provides a
novel method for deriving virial theorems for trapped Fermi
gases at the unitary limit. We also show that the
state-operator correspondence can be applied directly in
three spatial dimensions by calculating the scaling
dimensions of two- and three-fermion operators and finding
agreement with known exact results for energy levels of two
and three trapped fermions at the unitary
limit.},
Key = {fds152772}
}

@article{fds287639,
Author = {Mehen, T},
Title = {Nonrelativistic conformal field theory and trapped atoms:
Virial theorems and the state-operator correspondence in
three dimensions},
Journal = {Physical Review A - Atomic, Molecular, and Optical
Physics},
Volume = {78},
Number = {1},
Year = {2008},
ISSN = {1050-2947},
url = {http://dx.doi.org/10.1103/PhysRevA.78.013614},
Abstract = {The field theory of nonrelativistic fermions interacting via
contact interactions can be used to calculate the properties
of few-body systems of cold atoms confined in harmonic
traps. The state-operator correspondence of nonrelativistic
conformal field theory (NRCFT) shows that the energy
eigenvalues (in oscillator units) of N harmonically trapped
fermions can be calculated from the scaling dimensions of N
-fermion operators in the NRCFT. They are also in one-to-one
correspondence with zero energy, scale-invariant solutions
to the N -body problem in free space. We show that these two
mappings of the trapped fermion problem to free space
problems are related by an automorphism of the SL (2,R)
algebra of the conformal symmetry of fermions at the unitary
limit. This automorphism exchanges the internal Hamiltonian
of the gas with the trapping potential and hence provides a
method for deriving virial theorems for trapped Fermi gases
at the unitary limit. We also show that the state-operator
correspondence can be applied directly in three spatial
dimensions by calculating the scaling dimensions of two- and
three-fermion operators and finding agreement with known
exact results for energy levels of two and three trapped
fermions at the unitary limit. © 2008 The American Physical
Society.},
Doi = {10.1103/PhysRevA.78.013614},
Key = {fds287639}
}

@article{fds287654,
Author = {Fleming, S and Mehen, T},
Title = {Hadronic decays of the X(3872) to χcJ in effective field
theory},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {78},
Number = {9},
Year = {2008},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/0807.2674v2},
Abstract = {The decays of the X(3872) to P-wave quarkonia are calculated
under the assumption that it is a shallow bound state of
neutral charmed mesons. The X(3872) is described using an
effective theory of nonrelativistic D mesons and pions
(X-EFT). We calculate X(3872) decays by first matching heavy
hadron chiral perturbation theory (HHχPT) amplitudes for
D0D̄ *0→χcJ(π0,ππ) onto local operators in X-EFT, and
then using these operators to calculate the X(3872) decays.
This procedure reproduces the factorization theorems for
X(3872) decays to conventional quarkonia previously derived
using the operator product expansion. For single pion
decays, we find nontrivial dependence on the pion energy
from HHχPT diagrams with virtual D mesons. This nontrivial
energy dependence can potentially modify heavy-quark
symmetry predictions for the relative sizes of decay rates.
At leading order, decays to final states with two pions are
dominated by the final state χc1π0π0, with a branching
fraction just below that for the decay to χc1π0. Decays to
all other final states with two pions are highly suppressed.
© 2008 The American Physical Society.},
Doi = {10.1103/PhysRevD.78.094019},
Key = {fds287654}
}

@article{fds287655,
Author = {Kim, C and Leibovich, AK and Mehen, T},
Title = {Nonperturbative charming penguin contributions to isospin
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {78},
Number = {5},
Year = {2008},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/0805.1735},
Abstract = {Recent experimental data on the radiative decays B→Vγ,
where V is a light vector meson, find small isospin
violation in B→K*γ while isospin asymmetries in B→ργ
are of order 20%, with large uncertainties. Using
soft-collinear effective theory, we calculate isospin
asymmetries in these radiative B decays up to O(1/mb), also
including O(vαs) contributions from nonperturbative
charming penguins (NPCP). In the absence of NPCP
contributions, the theoretical predictions for the
asymmetries are a few percent or less. Including the NPCP
can significantly increase the isospin asymmetries for both
B→Vγ modes. We also consider the effect of the NPCP on
the branching ratio and CP asymmetries in B±→ V±γ. ©
2008 The American Physical Society.},
Doi = {10.1103/PhysRevD.78.054024},
Key = {fds287655}
}

@article{fds287617,
Author = {Mehen, T},
Title = {Heavy quark-diquark symmetry and &ChiPT for doubly heavy
baryons},
Journal = {Chiral Dynamics 2006 - Proceedings of the 5th International
Workshop on Chiral Dynamics, Theory and Experiment, CD
2006},
Pages = {299-301},
Year = {2007},
Month = {December},
Abstract = {A chiral Lagrangian incorporating heavy quark-diquark
symmetry is used to calculate doubly charm baryon
electromagnetic decays and chiral corrections to doubly
heavy baryon masses. Quenched and partially quenched
versions of the theory allow one to derive chiral
extrapolation formulae for lattice QCD simulations of doubly
heavy baryons.},
Key = {fds287617}
}

@article{fds287656,
Author = {Fleming, S and Kusunoki, M and Mehen, T and Kolck,
UV},
Title = {Pion interactions in the X(3872)},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {76},
Number = {3},
Year = {2007},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/hep-ph/0703168},
Abstract = {We consider pion interactions in an effective field theory
of the narrow resonance X(3872), assuming it is a weakly
bound molecule of the charm mesons D0D̄*0 and D*0D̄0.
Since the hyperfine splitting of the D0 and D*0 is only 7
MeV greater than the neutral pion mass, pions can be
produced near threshold and are nonrelativistic. We show
that pion exchange can be treated in perturbation theory and
calculate the next-to-leading-order correction to the
partial decay width Γ[X→D0D̄0π0]. © 2007 The American
Physical Society.},
Doi = {10.1103/PhysRevD.76.034006},
Key = {fds287656}
}

@article{fds287657,
Author = {Idilbi, A and Mehen, T},
Title = {Equivalence of soft and zero-bin subtractions at two
loops},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {76},
Number = {9},
Year = {2007},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/0707.1101},
Abstract = {Calculations of collinear correlation functions in
perturbative QCD and soft-collinear effective theory require
a prescription for subtracting soft or zero-bin
contributions in order to avoid double counting the
contributions from soft modes. At leading order in λ, where
λ is the soft-collinear effective theory expansion
parameter, the zero-bin subtractions have been argued to be
equivalent to convolution with soft Wilson lines. We give a
proof of the factorization of naive collinear Wilson lines
that is crucial for the derivation of the equivalence. We
then check the equivalence by computing the non-Abelian
two-loop mixed collinear-soft contribution to the jet
function in the quark form factor. These results demonstrate
the equivalence, which can be used to give a nonperturbative
definition of the zero-bin subtraction at lowest order in
λ. © 2007 The American Physical Society.},
Doi = {10.1103/PhysRevD.76.094015},
Key = {fds287657}
}

@article{fds287658,
Author = {Idilbi, A and Mehen, T},
Title = {On the equivalence of soft and zero-bin subtractions},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {75},
Number = {11},
Year = {2007},
ISSN = {1550-7998},
url = {http://arXiv.org/abs/hep-ph/0702022},
Abstract = {Zero-bin subtractions are required to avoid double counting
soft contributions in collinear loop integrals in
soft-collinear effective theory (SCET). In traditional
approaches to factorization, double counting is avoided by
dividing jet functions by matrix elements of soft Wilson
lines. In this paper, we compare the two approaches to
double counting, studying the quark form factor and deep
inelastic scattering (DIS) as xB→1 as examples. We explain
how the zero-bin subtractions in SCET are required to
reproduce the well-established factorization theorem for DIS
as xB→1. We study one-loop virtual contributions to the
quark form factor and real gluon emission diagrams in DIS.
The two approaches to double counting are equivalent if
dimensional regularization (DR) is used to regulate infrared
(IR) divergences. We discuss in detail ambiguities in the
calculation of one-loop scaleless integrals in DR in SCET
and perturbative QCD. We also demonstrate a nontrivial check
of the equivalence of the zero-bin subtraction and the soft
Wilson line subtraction in the virtual two-loop Abelian
contributions to the quark form factor. © 2007 The American
Physical Society.},
Doi = {10.1103/PhysRevD.75.114017},
Key = {fds287658}
}

@article{fds287616,
Author = {Leibovich, A and Fleming, S and Mehen, T},
Title = {J/φ photoproduction at the endpoint},
Journal = {Annual Meeting of the Division of Particles and Fields of
the American Physical Society, DPF 2006, and the Annual Fall
Meeting of the Japan Particle Physics Community},
Year = {2006},
Month = {January},
Key = {fds287616}
}

@article{fds287619,
Author = {Fleming, S and Leibovich, AK and Mehen, T},
Title = {J/Ψ photo-production at large z in soft collinear effective
theory},
Journal = {Proceedings of the Ringberg Workshop on New Trends in HERA
Physics 2005},
Pages = {239-250},
Year = {2006},
Month = {January},
url = {http://arxiv.org/abs/hep-ph/0512194},
Abstract = {One of the outstanding problems in J/Ψ physics is a
systematic understanding of the differential
photo-production cross section dσ/dz(γ+p → J/Ψ + X),
where z = E Ψ ,/E gamma; / in the proton rest frame. The
theoretical prediction based on the nonrelativistic QCD
(NRQCD) factorization formalism has a color-octet
contribution which grows rapidly in the endpoint region, z
-→ 1, spoiling perturbation theory. In addition there are
subleading operators which are enhanced by powers of 1/(1 -
z) and they must be resummed to all orders. Here an update
of a systematic analysis is presented. The approach used to
organize the endpoint behavior of the photoproduction cross
section is based on a combination of NRQCD and soft
collinear effective theory. While a final result is not yet
available, an intermediate result indicates that better
agreement between theory and data will be achieved in this
Co. Pte. Ltd.},
Key = {fds287619}
}

@article{fds287620,
Author = {Mehen, T},
Title = {Heavy quark-diquark symmetry and X PT for Doubly Heavy
Baryons},
Journal = {Annual Meeting of the Division of Particles and Fields of
the American Physical Society, DPF 2006, and the Annual Fall
Meeting of the Japan Particle Physics Community},
Pages = {299-301},
Year = {2006},
Month = {January},
Abstract = {A chiral Lagrangian incorporating heavy quark-diquark
symmetry is used to calculate doubly charm baryon
electromagnetic decays and chiral corrections to doubly
heavy baryon masses. Quenched and partially quenched
versions of the theory allow one to derive chiral
extrapolation formulae for lattice QCD simulations of doubly
heavy baryons.},
Key = {fds287620}
}

@article{fds43963,
Author = {S. Fleming and T. Mehen},
Title = {Doubly Heavy Baryons, Heavy Quark-Diquark Symmetry and
NRQCD},
Journal = {Phys. Rev. D 73, 034502},
Year = {2006},
url = {http://arxiv.org/abs/hep-ph/0509313},
Abstract = {In the heavy quark limit, properties of heavy mesons and
doubly heavy baryons are related by heavy quark-diquark
symmetry. This problem is reanalyzed in the framework of
Non-Relativistic QCD (NRQCD). We introduce a novel method
for deriving Potential NRQCD (pNRQCD) Lagrangians for
composite fields from vNRQCD, which contains quarks and
antiquarks as explicit degrees of freedom and maintains
manifest power counting in the velocity via a label
formalism. A Hubbard-Stratonovich transformation is used to
eliminate four quark interactions in vNRQCD and then quarks
and antiquarks are integrated out to get effective
Lagrangians for composite fields. This method is used to
rederive Lagrangians for the Q\bar Q and QQ sectors of
pNRQCD and give a correct derivation of the O(1/m_Q)
prediction for the hyperfine splitting of doubly heavy
baryons.},
Key = {fds43963}
}

@article{fds287637,
Author = {Hu, J and Mehen, T},
Title = {Chiral Lagrangian with heavy quark-diquark
symmetry},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {73},
Number = {5},
Year = {2006},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/hep-ph/0511321},
Abstract = {We construct a chiral Lagrangian for doubly heavy baryons
and heavy mesons that is invariant under heavy quark-diquark
symmetry violating operators. The theory is used to predict
the electromagnetic decay width of the J=32 member of the
ground state doubly heavy baryon doublet. Numerical
estimates are provided for doubly charm baryons. We also
calculate chiral corrections to doubly heavy baryon masses
and strong decay widths of low lying excited doubly heavy
baryons. © 2006 The American Physical Society.},
Doi = {10.1103/PhysRevD.73.054003},
Key = {fds287637}
}

@article{fds287638,
Author = {Fleming, S and Mehen, T},
Title = {Doubly heavy baryons, heavy quark-diquark symmetry, and
nonrelativistic QCD},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {73},
Number = {3},
Year = {2006},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.73.034502},
Abstract = {In the heavy quark limit, properties of heavy mesons and
doubly heavy baryons are related by heavy quark-diquark
symmetry. This problem is reanalyzed in the framework of
nonrelativistic QCD (NRQCD). We introduce a novel method for
deriving potential NRQCD (pNRQCD) Lagrangians for composite
fields from vNRQCD, which contains quarks and antiquarks as
explicit degrees of freedom and maintains manifest power
counting in the velocity via a label formalism. A
Hubbard-Stratonovich transformation is used to eliminate
four quark interactions in vNRQCD and then quarks and
antiquarks are integrated out to get effective Lagrangians
for composite fields. This method is used to rederive
Lagrangians for the QQ̄ and QQ sectors of pNRQCD and give a
correct derivation of the O(1/mQ) prediction for the
hyperfine splitting of doubly heavy baryons. © 2006 The
American Physical Society.},
Doi = {10.1103/PhysRevD.73.034502},
Key = {fds287638}
}

@article{fds287661,
Author = {Fleming, S and Leibovich, AK and Mehen, T},
Title = {Resummation of large endpoint corrections to color-octet
J/ψ photoproduction},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {74},
Number = {11},
Year = {2006},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/hep-ph/0607121},
Abstract = {An unresolved problem in J/ψ phenomenology is a systematic
understanding of the differential photoproduction cross
section, dσ/dz[γ+p→J/ψ+X], where z=Eψ/Eγ in the
proton rest frame. In the nonrelativistic QCD (NRQCD)
factorization formalism, fixed-order perturbative
calculations of color-octet mechanisms suffer from large
perturbative and nonperturbative corrections that grow
rapidly in the endpoint region, z→1. In this paper, NRQCD
and soft collinear effective theory are combined to resum
these large corrections to the color-octet photoproduction
cross section. We derive a factorization theorem for the
endpoint differential cross section involving the parton
distribution function and the color-octet J/ψ shape
functions. A one-loop matching calculation explicitly
confirms our factorization theorem at next-to-leading order.
Large perturbative corrections are resummed using the
renormalization group. The calculation of the color-octet
contribution to dσ/dz is in qualitative agreement with
data. Quantitative tests of the universality of color-octet
matrix elements require improved knowledge of shape
functions entering these calculations as well as resummation
of the color-singlet contribution which accounts for much of
the total cross section and also peaks near the endpoint. ©
2006 The American Physical Society.},
Doi = {10.1103/PhysRevD.74.114004},
Key = {fds287661}
}

@article{fds287662,
Author = {Mehen, T and Tiburzi, BC},
Title = {Doubly heavy baryons and quark-diquark symmetry in quenched
and partially quenched chiral perturbation
theory},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {74},
Number = {5},
Year = {2006},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/hep-lat/0607023},
Abstract = {We extend the chiral Lagrangian with heavy quark-diquark
symmetry to quenched and partially quenched theories. These
theories are used to derive formulas for the chiral
extrapolation of masses and hyperfine splittings of double
heavy baryons in lattice QCD simulations. A quark-diquark
symmetry prediction for the hyperfine splittings of heavy
mesons and doubly heavy baryons is rather insensitive to
chiral corrections in both quenched and partially quenched
QCD. Extrapolation formulas for the doubly heavy baryon
electromagnetic transition moments are also determined for
the partially quenched theory. © 2006 The American Physical
Society.},
Doi = {10.1103/PhysRevD.74.054505},
Key = {fds287662}
}

@article{fds287668,
Author = {Mehen, T and Springer, RP},
Title = {Even- and Odd-Parity Charmed Meson Masses in Heavy Hadron
Chiral Perturbation Theory},
Journal = {Phys Rev D},
Volume = {72},
Number = {034006},
Pages = {1-12},
Year = {2005},
Month = {March},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/hep-ph/0503134},
Abstract = {We derive mass formulas for the ground state, JP=0- and 1-,
and first excited even-parity, JP=0+ and 1+, charmed mesons
including one-loop chiral corrections and O(1/mc)
counterterms in heavy hadron chiral perturbation theory. We
show that including these counterterms is critical for
fitting the current data. We find that certain parameter
relations in the parity doubling model are not renormalized
at one-loop, providing a natural explanation for the
observed equality of the hyperfine splittings of ground
state and excited doublets. Â© 2005 The American Physical
Society.},
Doi = {10.1103/PhysRevD.72.034006},
Key = {fds287668}
}

@article{fds287669,
Author = {Mehen, T},
Title = {Excited Ds (and pentaquarks) in chiral
perturbation theory},
Journal = {Acta Physica Polonica, Series B.},
Volume = {36},
Number = {7},
Pages = {2341-2350},
Year = {2005},
ISSN = {0587-4254},
url = {http://arxiv.org/abs/hep-ph/0506219},
Abstract = {I present results of a heavy hadron chiral perturbation
theory analysis of the decays and masses of the recently
discovered excited charm mesons. The present data on the
electromagnetic branching ratios are consistent with heavy
quark symmetry predictions and disfavor a molecular
interpretation of these states. I also discuss model
independent predictions for the strong decays of pentaquarks
in the 10̄ representation of SU(3) which can be used to
constrain the angular momentum and parity quantum numbers of
these states.},
Key = {fds287669}
}

@article{fds287670,
Author = {Mehen, T and Tiburzi, BC},
Title = {Quarks with twisted boundary conditions in the epsilon
regime},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {72},
Number = {1},
Pages = {1-9},
Year = {2005},
ISSN = {1550-7998},
url = {http://arxiv.org/abs/hep-lat/0505014},
Abstract = {We study the effects of twisted boundary conditions on the
quark fields in the epsilon regime of chiral perturbation
theory. We consider the SU(2)LxSU(2)R chiral theory with
nondegenerate quarks and the SU(3)LxSU(3)R chiral theory
with massless up and down quarks and massive strange quarks.
The partition function and condensate are derived for each
theory. Because flavor-neutral Goldstone bosons are
unaffected by twisted boundary conditions chiral symmetry is
still restored in finite volumes. The dependence of the
condensate on the twisting parameters can be used to extract
the pion decay constant from simulations in the epsilon
regime. The relative contribution to the partition function
from sectors of different topological charge is numerically
insensitive to twisted boundary conditions. © 2005 The
American Physical Society.},
Doi = {10.1103/PhysRevD.72.014501},
Key = {fds287670}
}

@article{fds305719,
Author = {Mehen, T and Springer, RP},
Title = {Even- and odd-parity charmed meson masses in heavy hadron
chiral perturbation theory},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {72},
Number = {3},
Pages = {1-12},
Year = {2005},
ISSN = {1550-7998},
url = {http://dx.doi.org/10.1103/PhysRevD.72.034006},
Abstract = {We derive mass formulas for the ground state, JP=0- and 1-,
and first excited even-parity, JP=0+ and 1+, charmed mesons
including one-loop chiral corrections and O(1/mc)
counterterms in heavy hadron chiral perturbation theory. We
show that including these counterterms is critical for
fitting the current data. We find that certain parameter
relations in the parity doubling model are not renormalized
at one-loop, providing a natural explanation for the
observed equality of the hyperfine splittings of ground
state and excited doublets. © 2005 The American Physical
Society.},
Doi = {10.1103/PhysRevD.72.034006},
Key = {fds305719}
}

@article{fds287613,
Author = {Mehen, T and Springer, RP},
Title = {Heavy-quark symmetry and the electromagnetic decays of
excited charmed strange mesons},
Journal = {Physical Review D - Particles, Fields, Gravitation, and
Cosmology},
Volume = {70},
Number = {7},
Pages = {074014-1-074014-12},
Year = {2004},
Month = {January},
ISSN = {0556-2821},
url = {http://dx.doi.org/10.1103/PhysRevD.70.074014},
Abstract = {Heavy-hadron chiral perturbation theory ([Formula
Presented]) is applied to the decays of the even-parity
charmed strange mesons, [Formula Presented] and [Formula
Presented]. Heavy-quark spin-symmetry predicts the branching
fractions for the three electromagnetic decays of these
states to the ground states [Formula Presented] and [Formula
Presented] in terms of a single parameter. The resulting
predictions for two of the branching fractions are
significantly higher than current upper limits from the CLEO
experiment. Leading corrections to the branching ratios from
chiral loop diagrams and spin-symmetry violating operators
in the [Formula Presented] Lagrangian can naturally account
for this discrepancy. Finally the proposal that the [Formula
Presented] ([Formula Presented] ) is a hadronic bound state
of a [Formula Presented] meson and a kaon is considered.
Leading order predictions for electromagnetic branching
ratios in this molecular scenario are in very poor agreement
with existing data. © 2004 The American Physical
Society.},
Doi = {10.1103/PhysRevD.70.074014},
Key = {fds287613}
}

@article{fds29799,
Author = {T. Mehen and R. P. Springer},
Title = {Heavy-Quark Symmetry and the Electromagnetic Decays of
Excited Charm Strange Mesons},
Journal = {Phys. Rev. D70, 074014},
Year = {2004},
url = {http://arxiv.org/abs/hep-ph/0407181},
Abstract = {Heavy-hadron chiral perturbation theory (HH$\chi$PT) is
applied to the decays of the even-parity charmed strange
mesons, D_{s0}(2317) and D_{s1}(2460). Heavy-quark spin
symmetry predicts the branching fractions for the three
electromagnetic decays of these states to the ground states
D_s and D_s^* in terms of a single parameter. The resulting
predictions for two of the branching fractions are
significantly higher than current upper limits from the CLEO
experiment. Leading corrections to the branching ratios from
chiral loop diagrams and spin-symmetry violating operators
in the HH$\chi$PT Lagrangian can naturally account for this
discrepancy. Finally the proposal that the D_{s0}(2317)
(D_{s1}(2460)) is a hadronic bound state of a D (D^*) meson
and a kaon is considered. Leading order predictions for
electromagnetic branching ratios in this molecular scenario
are in very poor agreement with existing
data.},
Key = {fds29799}
}

@article{fds287612,
Author = {Braaten, E and Kusunoki, M and Jia, Y and Mehen, T},
Title = {Λ<inf>c</inf><sup>+</sup>/Λ<inf>c</inf><sup>-</sup>
recombination},
Journal = {Physical Review D: Particles, Fields, Gravitation and
Cosmology},
Volume = {70},
Number = {5},
Pages = {054021-1-054021-5},
Year = {2004},
ISSN = {0556-2821},
url = {http://dx.doi.org/10.1103/PhysRevD.70.054021},
Abstract = {Asymmetries in the hadroproduction of charm particles
directly probe power corrections to the QCD factorization
theorems. In this paper, the heavy-quark recombination
mechanism, a power correction that explains charm meson
asymmetries, is extended to charm baryons. In this
mechanism, a light quark participates in the hard-scattering
that creates a charm quark and they hadronize together into
a charm baryon. This provides a natural and economical
explanation for the Λ&lt;inf&gt;c&lt;/inf&gt;&lt;sup&gt;+&lt;/sup&gt;/Λ&lt;inf&gt;c&lt;/inf&gt;
&lt;sup&gt;-&lt;/sup&gt; asymmetries measured in πN pN
collisions.},
Doi = {10.1103/PhysRevD.70.054021},
Key = {fds287612}
}

@article{fds287635,
Author = {Braaten, E and Kusunoki, M and Jia, Y and Mehen, T},
Title = {Λc+/Λc-
recombination},
Journal = {Physical Review D - Particles, Fields, Gravitation and
Cosmology},
Volume = {70},
Number = {5},
Pages = {054021-1-054021-5},
Year = {2004},
url = {http://dx.doi.org/10.1103/PhysRevD.70.054021},
Abstract = {Asymmetries in the hadroproduction of charm particles
directly probe power corrections to the QCD factorization
theorems. In this paper, the heavy-quark recombination
mechanism, a power correction that explains charm meson
asymmetries, is extended to charm baryons. In this
mechanism, a light quark participates in the hard-scattering
that creates a charm quark and they hadronize together into
a charm baryon. This provides a natural and economical
explanation for the Λc+/Λc- asymmetries measured in πN pN
collisions.},
Doi = {10.1103/PhysRevD.70.054021},
Key = {fds287635}
}

@article{fds287663,
Author = {Mehen, T},
Title = {Charm production asymmetries from heavy-quark
recombination},
Journal = {Journal of Physics G: Nuclear and Particle
Physics},
Volume = {30},
Number = {1},
Pages = {S295-S304},
Year = {2004},
url = {http://arxiv.org/abs/hep-ph/0306178},
Abstract = {Charm asymmetries in fixed-target hadroproduction
experiments are sensitive to power corrections to the QCD
factorization theorem for heavy quark production. A power
correction called heavy-quark recombination has recently
been proposed to explain these asymmetries. In heavy-quark
recombination, a light quark or antiquark participates in a
hard scattering which produces a charm-anticharm quark pair.
The light quark or antiquark emerges from the scattering
with small momentum in the rest frame of the charm quark,
and together they hadronize into a charm particle. The cross
section for this process can be calculated within
perturbative QCD up to an overall normalization. Heavy-quark
recombination explains the observed D meson and ΛC
asymmetries with a minimal set of universal nonperturbative
parameters.},
Doi = {10.1088/0954-3899/30/1/035},
Key = {fds287663}
}

@article{fds287664,
Author = {Mehen, T},
Title = {Recent developments in heavy quark and quarkonium
production},
Journal = {Acta Physica Polonica, Series B.},
Volume = {35},
Number = {1},
Pages = {121-129},
Year = {2004},
ISSN = {0587-4254},
url = {http://arxiv.org/abs/hep-ph/0312239},
Abstract = {Recent measurements of J/ψ production in e+e- colliders
pose a challenge to the NRQCD factorization theorem for
quarkonium production. Discrepancies between leading order
calculations of color-octet contributions and the momentum
distribution of J/ψ observed by Belle and BaBar are
resolved by resumming large perturbative and nonperturbative
corrections that are enhanced near the kinematic endpoint.
The large cross sections for J/ψcc̄ and double quarkonium
production remain poorly understood. Nonperturbative effects
in fixed-target hadroproduction of open charm are also
discussed. Large asymmetries in the production of charm
mesons and baryons probe nonperturbative corrections to the
QCD factorization theorem. A power correction called
heavy-quark recombination can economically explain these
asymmetries with a few universal parameters.},
Key = {fds287664}
}

@article{fds287665,
Author = {Braaten, E and Kusunoki, M and Jia, Y and Mehen, T},
Title = {$\Lambda_c^+/\Lambda^-_c$ Asymmetry in Hadroproduction for
Heavy-Quark Recombination},
Journal = {Phys. Rev. D70, 054021},
Year = {2004},
url = {http://arxiv.org/abs/hep-ph/0304280},
Abstract = {Asymmetries in the hadroproduction of charm particles
directly probe power corrections to the QCD factorization
theorems. In this paper, the heavy-quark recombination
mechanism, a power correction that explains charm meson
asymmetries, is extended to charm baryons. In this
mechanism, a light quark participates in the hard scattering
that creates a charm quark and they hadronize together into
a charm baryon. This provides a natural and economical
explanation for the \Lambda_c^+/\Lambda_c^- asymmetries
measured in \pi N and p N collisions.},
Key = {fds287665}
}

@article{fds287666,
Author = {Mehen, T and Springer, RP},
Title = {Heavy-quark symmetry and the electromagnetic decays of
excited charmed strange mesons},
Journal = {Physical Review D - Particles, Fields, Gravitation and
Cosmology},
Volume = {70},
Number = {7},
Pages = {074014-1-074014-12},
Year = {2004},
url = {http://dx.doi.org/10.1103/PhysRevD.70.074014},
Abstract = {Heavy-hadron chiral perturbation theory (HHχPT) is applied
to the decays of the even-parity charmed strange mesons,
Ds0(2317) and Ds1(2460). Heavy-quark spin-symmetry predicts
the branching fractions for the three electromagnetic decays
of these states to the ground states Ds and Ds* in terms of
a single parameter. The resulting predictions for two of the
branching fractions are significantly higher than current
upper limits from the CLEO experiment. Leading corrections
to the branching ratios from chiral loop diagrams and
spin-symmetry violating operators in the HHχPT Lagrangian
can naturally account for this discrepancy. Finally the
proposal that the Ds0(2317) (D s1(2460)) is a hadronic bound
state of a D(D*) meson and a kaon is considered. Leading
order predictions for electromagnetic branching ratios in
this molecular scenario are in very poor agreement with
existing data.},
Doi = {10.1103/PhysRevD.70.074014},
Key = {fds287666}
}

@article{fds287667,
Author = {Mehen, T and Schat, C},
Title = {Determining pentaquark quantum numbers from strong
decays},
Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and
High-Energy Physics},
Volume = {588},
Number = {1-2},
Pages = {67-73},
Year = {2004},
url = {http://arxiv.org/abs/hep-ph/0401107},
Abstract = {Assuming that the recently observed Θ+ and Ξ- are members
of an anti-decuplet of SU(3), decays to ground state baryons
and mesons are calculated using an effective Lagrangian
which incorporates chiral and SU(3) symmetry. We consider
the possible quantum number assignments JΠ=12±,32± and
calculate ratios of partial widths. The branching ratios of
exotic cascades can be used to discriminate between even and
B.V.},
Doi = {10.1016/j.physletb.2004.03.039},
Key = {fds287667}
}

@article{fds287633,
Author = {Kaiser, R and Manohar, AV and Mehen, T},
Title = {Isospin violation in e+e- →
BB̄},
Journal = {Physical Review Letters},
Volume = {90},
Number = {14},
Pages = {142001/1-142001/4},
Year = {2003},
url = {http://arxiv.org/abs/hep-ph/0208194},
Abstract = {An overview is given of the computation of R+/0. The result
depends on two parameters: the Β*Βπ coupling and δc,
which represents the isospin violating part of the Y(4S)
coupling to Β̄Β states.},
Doi = {10.1103/PhysRevLett.90.142001},
Key = {fds287633}
}

@article{fds287671,
Author = {Fleming, S and Leibovich, AK and Mehen, T},
Title = {Resumming the color-octet contribution to
e+e-→J/ψ+X},
Journal = {Physical Review D: Particles, Fields, Gravitation and
Cosmology},
Volume = {68},
Number = {9},
Year = {2003},
ISSN = {0556-2821},
url = {http://arxiv.org/abs/hep-ph/0306139},
Abstract = {Recent observations of the spectrum of J/ψ produced in e+e-
collisions at the Υ(4S) resonance are in conflict with
fixed-order calculations using the nonrelativistic QCD
effective field theory. One problem is that leading order
color-octet mechanisms predict an enhancement of the cross
section for J/ψ with a maximal energy that is not observed
in the data. However, in this region of phase space large
perturbative corrections (Sudakov logarithms) as well as
enhanced nonperturbative effects are important. In this
paper we use the newly developed soft-collinear effective
theory (SCET) to systematically include these effects. We
find that these corrections significantly broaden the
color-octet contribution to the J/ψ spectrum. Our
calculation employs a one-stage renormalization group
evolution rather than the two-stage evolution used in
previous SCET calculations. We give a simple argument for
why the two methods yield identical results to lowest order
in the SCET power counting. © The American Physical
Society.},
Doi = {10.1103/PhysRevD.68.094011},
Key = {fds287671}
}

@article{fds287672,
Author = {Mehen, T and Wecht, B},
Title = {Gauge Fields and Scalars in Rolling Tachyon
Backgrounds},
Journal = {JHEP 0302},
Volume = {7},
Number = {2},
Pages = {58},
Year = {2003},
url = {http://arxiv.org/abs/hep-th/0206212},
Abstract = {We investigate the dynamics of gauge and scalar fields on
unstable D-branes with rolling tachyons. Assuming an FRW
metric on the brane, we find a solution of the tachyon
equation of motion which is valid for arbitrary tachyon
potentials and scale factors. The equations of motion for a
U(1) gauge field and a scalar field in this background are
derived. These fields see an effective metric which differs
from the original FRW metric. The field equations receive
large corrections due to the curvature of the effective
metric as well as the time variation of the gauge coupling.
The equations of state for these fields resemble those of
nonrelativistic matter rather than massless
particles.},
Key = {fds287672}
}

@article{fds305718,
Author = {Mehen, T and Wecht, B},
Title = {Gauge fields and scalars in rolling tachyon
backgrounds},
Journal = {Journal of High Energy Physics},
Volume = {7},
Number = {2},
Pages = {1313-1326},
Year = {2003},
Abstract = {We investigate the dynamics of gauge and scalar fields on
unstable D-branes with rolling tachyons. Assuming an FRW
metric on the brane, we find a solution of the tachyon
equation of motion which is valid for arbitrary tachyon
potentials and scale factors. The equations of motion for a
U(1) gauge field and a scalar field in this background are
derived. These fields see an effective metric which differs
from the original FRW metric. The field equations receive
large corrections due to the curvature of the effective
metric as well as the time variation of the gauge coupling.
The equations of state for these fields resemble those of
nonrelativistic matter rather than those of massless
Key = {fds305718}
}

@article{fds3887,
Author = {E. Braaten and Yu Jia and T. Mehen},
Title = {The Leading Particle Effect From Heavy-Quark
Recombination},
Journal = {Phys. Rev. Lett. 89, 122002},
Year = {2002},
url = {http://arxiv.org/abs/hep-ph/0205149},
enhancement of the cross section for a charmed hadron D in
the forward direction of the beam when the beam hadron has a
valence parton in common with the D. The large D+/D-
asymmetry observed by the E791 experiment is an example of
this phenomenon. We show that the heavy-quark recombination
mechanism provides an economical explanation for this
effect. In particular, the D+/D- asymmetry can be fit
reasonably well using a single parameter whose value is
consistent with a recent determination from charm
photoproduction.},
Key = {fds3887}
}

@article{fds287631,
Author = {Braaten, E and Hammer, H-W and Mehen, T},
Title = {Dilute Bose-Einstein condensate with large scattering
length},
Journal = {Physical Review Letters},
Volume = {88},
Number = {4},
Pages = {404011-404014},
Year = {2002},
url = {http://arxiv.org/abs/cond-mat/0108380},
Abstract = {A dilute Bose gas of atoms with large scattering length as
compared to their range of interaction was studied. The
energy density of a homogenous Bose-Einstein condensate
(BEC) was calculated up to the second order in the
low-density expansion. The instability due to three-body
recombination was reflected by the imaginary part of a
second order correction to energy density. The coefficient
of the three body mean-field term in energy density was
calculated which was found to be very large for Efimov state
near threshold.},
Doi = {10.1103/PhysRevLett.88.040401},
Key = {fds287631}
}

@article{fds287632,
Author = {Braaten, E and Jia, Y and Mehen, T},
Title = {Leading-particle effect from heavy-quark
recombination},
Journal = {Physical Review Letters},
Volume = {89},
Number = {12},
Pages = {1220021-1220024},
Year = {2002},
ISSN = {0031-9007},
Abstract = {The leading particle effect was presented quantitatively and
economically by the heavy-quark recombination mechanism. It
was found that the leading particle effect in charm
hadroproduction is an enhancement of the cross section for a
charmed hadron in the forward direction of the beam. The
D+/D- asymmetry was also found to fit using a single
parameter whose value was consistent with a determination
from charm photoproduction.},
Key = {fds287632}
}

@article{fds287659,
Author = {Braaten, E and Yu, J and Mehen, T},
Title = {B production asymmetries in perturbative
QCD},
Journal = {Physical Review D: Particles, Fields, Gravitation and
Cosmology},
Volume = {66},
Number = {3},
Year = {2002},
ISSN = {0556-2821},
url = {http://arxiv.org/abs/hep-ph/0108201},
Abstract = {This paper explores a new mechanism for B production in
which a b̄ quark combines with a light parton from the
hard-scattering process before hadronizing into the 5
hadron. This heavy-quark recombination mechanism can be
calculated within perturbative QCD up to a few
nonperturbative constants. Though suppressed at large
transverse momentum by a factor ∧ QCDm b/p ⊥2 relative
to b̄ fragmentation production, it can be important at
large rapidities. A signature for this heavy-quark
recombination mechanism in pp̄ colliders is the presence of
rapidity asymmetries in B cross sections. Given reasonable
assumptions about the size of nonperturbative parameters
entering the calculation, we find that the asymmetries are
only significant for rapidities larger than those currently
probed by collider experiments. © 2002 The American
Physical Society.},
Doi = {10.1103/PhysRevD.66.034003},
Key = {fds287659}
}

@article{fds287660,
Author = {Manohar, AV and Mehen, T and Pirjol, D and Stewart,
IW},
Title = {Reparameterization invariance for collinear
operators},
Journal = {Physics Letters B},
Volume = {539},
Number = {1-2},
Pages = {59-66},
Year = {2002},
ISSN = {0370-2693},
url = {http://arxiv.org/abs/hep-ph/0204229},
Abstract = {We discuss restrictions on operators in the soft-collinear
effective theory (SCET) which follow from the ambiguity in
the decomposition of collinear momenta and the freedom in
the choice of light-like basis vectors n and n̄. Invariance
of SCET under small changes in n and/or n̄ implies a
symmetry of the effective theory that constrains the form of
allowed operators with collinear fields. The restrictions
occur at a given order in the power counting as well as
between different orders. As an example, we present the
complete set of higher order operators that are related to
the collinear quark kinetic term. ©2002 Elsevier Science
Doi = {10.1016/S0370-2693(02)02029-4},
Key = {fds287660}
}

@article{fds287673,
Author = {Braaten, E and Jia, Y and Mehen, T},
Title = {Charm-anticharm asymmetries in photoproduction from
heavy-quark recombination},
Journal = {Physical Review D: Particles, Fields, Gravitation and
Cosmology},
Volume = {66},
Number = {1 II},
Pages = {140031-1400310},
Year = {2002},
ISSN = {0556-2821},
url = {http://arxiv.org/abs/hep-ph/0111296},
Abstract = {The asymmetries between charm and anticharm mesons observed
in fixed-target photoproduction experiments are an order of
magnitude larger than the asymmetries predicted by
conventional perturbative QCD. We show that these charm
meson asymmetries can be explained by a heavy-quark
recombination mechanism for heavy meson production. In this
process, a charm quark combines with a light antiquark from
the hardscattering process and they subsequently hadronize
into a state including the charm meson. This recombination
mechanism can be calculated within perturbative QCD up to
some nonperturbative constants. After using symmetries of
QCD to reduce the number of free parameters to two, we
obtain a good fit to all the data on the asymmetries for
charmed mesons from the E687 and E691 experiments.},
Doi = {10.1103/PhysRevD.66.014003},
Key = {fds287673}
}

@article{fds287692,
Author = {Hammer, H-W and Mehen, T},
Title = {Range corrections to doublet S-wave neutron-deuteron
scattering},
Journal = {Physics Letters B},
Volume = {516},
Number = {3-4},
Pages = {353-361},
Year = {2001},
ISSN = {0370-2693},
url = {http://dx.doi.org/10.1016/S0370-2693(01)00918-2},
Abstract = {We calculate the range corrections to S-wave
neutron-deuteron scattering in the doublet channel (S = 1/2)
to first order in r/a where a is the scattering length and r
the effective range. Ultraviolet divergences appearing at
this order can be absorbed into a redefinition of the
leading order three-body force. The corrections to the
elastic scattering amplitude below the deuteron breakup
threshold are computed. Inclusion of the range corrections
gives good agreement with measured scattering data and
potential model calculations. © 2001 Elsevier Science B.V.
Doi = {10.1016/S0370-2693(01)00918-2},
Key = {fds287692}
}

@article{fds287693,
Author = {Hammer, H-W and Mehen, T},
Title = {A renormalized equation for the three-body system with
short-range interactions},
Journal = {Nuclear Physics A},
Volume = {690},
Number = {4},
Pages = {535-546},
Year = {2001},
url = {http://dx.doi.org/10.1016/S0375-9474(00)00710-7},
Abstract = {We study the three-body system with short-range interactions
characterized by an unnaturally large two-body scattering
length. We show that the off-shell scattering amplitude is
cutoff independent up to power corrections. This allows us
to derive an exact renormalization group equation for the
three-body force. We also obtain a renormalized equation for
the off-shell scattering amplitude. This equation is
invariant under discrete scale transformations. The
periodicity of the spectrum of bound states originally
observed by Efimov is a consequence of this symmetry. The
functional dependence of the three-body scattering length on
the two-body scattering length can be obtained analytically
using the asymptotic solution to the integral equation. An
analogous formula for the three-body recombination
coefficient is also obtained. © 2001 Elsevier Science
B.V.},
Doi = {10.1016/S0375-9474(00)00710-7},
Key = {fds287693}
}

@article{fds322013,
Author = {Fleming, S and Mehen, T and Stewart, IW},
Title = {NN scattering 3S1-3D1
Journal = {Physical Review C - Nuclear Physics},
Volume = {61},
Number = {4},
Pages = {440051-440059},
Year = {2000},
Month = {January},
Abstract = {The 3 S 1 - 3 D 1 mixing angle for nucleon-nucleon
scattering ∈1 is calculated to next-to-next-to-leading
order in an effective field theory with perturbative pions.
Without pions, the low energy theory fits the observed ∈1
well for momenta less than∼50 MeV. Including pions
perturbatively significantly improves the agreement with
data for momenta up to ∼150 MeV with one less parameter.
Furthermore, for these momenta the accuracy of our
calculation is similar to an effective field theory
calculation in which the pion is treated nonperturbatively.
This gives phenomenological support for a perturbative
treatment of pions in low energy two-nucleon processes. We
explain why it is necessary to perform spin and isospin
traces in d dimensions when regulating divergences with
dimensional regularization in higher partial wave
amplitudes.},
Key = {fds322013}
}

@article{fds3907,
Author = {T. Mehen and I.W. Stewart},
Title = {Nucleon-Nucleon Effective Field Theory at NNLO: Radiation
Pions and $^1S_0$ Phase Shift},
Series = {Proc. Inst. Nucl. Theor. 9},
Booktitle = {Proceedings of the INT Workshop on Nuclear Physics with
Effective Field Theory},
Publisher = {World Scientific},
Editor = {P. Bedaque and M. Savage and R. Seki and U. L. Van
Kolck},
Year = {2000},
Abstract = {Low energy phenomena involving two nucleons can be
successfully described using effective field theory. Because
of the relatively large expansion parameter, it is only at
next-to-next-to-leading order (NNLO) where one can expect to
see agreement with experiment at the few percent level. The
first part of this talk will focus on radiation pion
effects, which first appear at NNLO. The power counting for
radiation pions is simple for center of mass momentum
p~\sqrt{M m_pi}=Q_r, the threshold for pion production. We
explain how graphs calculated with the Q_r power counting
scale for p~m_\pi. The Q_r^3 radiation pion contributions to
nucleon-nucleon scattering are suppressed by inverse powers
of the S-wave scattering lengths. However, we point out that
order Q_r^4 radiation contributions might give a NNLO
contribution for p~m_pi. In the second part of the talk,
results for the potential pion and contact interaction part
of the NNLO 1S0 phase shift are presented. We emphasize the
importance of eliminating spurious poles in the expression
for the amplitude at each order in the perturbative
expansion. Doing this leaves a total of three free
parameters at NNLO. We obtain a good fit to the 1S0 phase
shift.},
Key = {fds3907}
}

@article{fds287630,
Author = {Mehen, T and Stewart, IW and Wise, MB},
Title = {The physics of the centrality dependence of elliptic
flow},
Journal = {Physics Letters B},
Volume = {474},
Number = {1-2},
Pages = {27-32},
Year = {2000},
ISSN = {0370-2693},
url = {http://dx.doi.org/10.1016/S0370-2693(00)00017-4},
Abstract = {The centrality dependence of elliptic flow and how it is
related to the physics of expansion of the system created in
high energy nuclear collisions is discussed. Since in the
hydro limit the centrality dependence of elliptic flow is
mostly defined by the elliptic anisotropy of the overlapping
region of the colliding nuclei, and in the low density limit
by the product of the elliptic anisotropy and the
multiplicity, we argue that the centrality dependence of
elliptic flow should be a good indicator of the degree of
equilibration reached in the reaction. Then we analyze
experimental data obtained at AGS and SPS energies. The
observed difference in the centrality dependence of elliptic
flow could imply a transition from a hadronic to a partonic
nature of the system evolution. Finally we exploit the
multiplicity dependence of elliptic flow to make qualitative
Science B.V.},
Doi = {10.1016/S0370-2693(00)00017-4},
Key = {fds287630}
}

@article{fds287682,
Author = {Mehen, T and Stewart, IW},
Title = {Radiation pions in two-nucleon effective field
theory},
Journal = {Nuclear Physics A},
Volume = {665},
Number = {1-2},
Pages = {164-182},
Year = {2000},
Abstract = {For interactions involving two or more nucleons it is useful
to divide pions into three classes: potential, radiation,
and soft. The momentum threshold for the production of
pions can be included systematically with a power counting
contribute to NN scattering are evaluated in the PDS and OS
renormalization schemes and are found to give a small
contribution. The power counting for soft pion contributions
is also discussed. © 2000 Elsevier Science B.V. All rights
reserved.},
Key = {fds287682}
}

@article{fds287684,
Author = {Fleming, S and Mehen, T and Stewart, IW},
Title = {The NN Scattering $^3S_1-{}^3D_1$ Mixing Angle at
NNLO},
Journal = {Phys. Rev. C},
Volume = {61},
Number = {4},
Pages = {044005},
Year = {2000},
Abstract = {The 3S1-3D1 mixing angle for nucleon-nucleon scattering,
epsilon_1, is calculated to next-to-next-to-leading order in
an effective field theory with perturbative pions. Without
pions, the low energy theory fits the observed epsilon_1
well for momenta less than $\sim 50$ MeV. Including pions
perturbatively significantly improves the agreement with
data for momenta up to $\sim 150$ MeV with one less
parameter. Furthermore, for these momenta the accuracy of
our calculation is similar to an effective field theory
calculation in which the pion is treated non-perturbatively.
This gives phenomenological support for a perturbative
treatment of pions in low energy two-nucleon processes. We
explain why it is necessary to perform spin and isospin
traces in d dimensions when regulating divergences with
dimensional regularization in higher partial wave
amplitudes.},
Key = {fds287684}
}

@article{fds287685,
Author = {Mehen, T and Stewart, IW and Wise, MB},
Title = {Conformal Invariance for Non-Relativistic Field
Theory},
Journal = {Phys. Lett. B},
Volume = {474},
Pages = {145-152},
Year = {2000},
Abstract = {Momentum space Ward identities are derived for the amputated
n-point Green's functions in 3+1 dimensional
non-relativistic conformal field theory. For n=4 and 6 the
implications for scattering amplitudes (i.e. on-shell
amputated Green's functions) are considered. Any scale
invariant 2-to-2 scattering amplitude is also conformally
invariant. However, conformal invariance imposes constraints
on off-shell Green's functions and the three particle
scattering amplitude which are not automatically satisfied
if they are scale invariant. As an explicit example of a
conformally invariant theory we consider non-relativistic
particles in the infinite scattering length
limit.},
Key = {fds287685}
}

@article{fds287686,
Author = {Fleming, S and Mehen, T and Stewart, IW},
Title = {NNLO corrections to nucleon-nucleon scattering and
perturbative pions},
Journal = {Nuclear Physics A},
Volume = {677},
Number = {1-4},
Pages = {313-366},
Year = {2000},
Abstract = {The 1S0, 3S1, and 3D1 nucleon-nucleon scattering phase
shifts are calculated at next-to-next-to-leading order
(NNLO) in an effective field theory. Predictions for the
1P1, 3P0,1,2, 1D2, and 3D2,3 phase shifts at this order are
also compared with data. The calculations treat pions
perturbatively and include the NNLO contributions from order
Qr3 and Qr4 radiation pion graphs. In the 3S1, 3D1 and 3P0,2
channels we find large disagreement with the Nijmegen
partial-wave analysis at NNLO. These spin triplet channels
have large corrections from graphs with two potential pion
exchange which do not vanish in the chiral limit. We compare
our results to calculations within the Weinberg approach,
and find that in some spin triplet channels the summation of
potential pion diagrams seems to be necessary to reproduce
the observed phase shifts. In the spin singlet channels the
nonperturbative treatment of potential pions does not afford
a significant improvement over the perturbative approach. ©
2000 Elsevier Science B.V.},
Key = {fds287686}
}

@article{fds287687,
Author = {Gomis, J and Kleban, M and Mehen, T and Rangamani, M and Shenker,
S},
Title = {Noncommutative Gauge Dynamics from the String World
Sheet},
Journal = {JHEP},
Volume = {8},
Number = {8 PART A},
Pages = {11},
Year = {2000},
Abstract = {We show how string theory can be used to reproduce the
one-loop two-point photon amplitude in noncommutative U(1)
gauge theory. Using a simple realization of the gauge theory
in bosonic string theory, we extract from a string cylinder
computation in the decoupling limit the exact one loop field
theory result. The result is obtained entirely from the
region of moduli space where massless open strings dominate.
Our computation indicates that the unusual IR/UV
singularities of noncommutative field theory do not come
from closed string modes in any simple way.},
Key = {fds287687}
}

@article{fds287688,
Author = {Gomis, J and Mehen, T},
Title = {Space-time noncommutative field theories and
unitarity},
Journal = {Nuclear Physics B},
Volume = {591},
Number = {1-2},
Pages = {265-276},
Year = {2000},
Abstract = {We study the perturbative unitarity of noncommutative scalar
field theories. Field theories with space-time
noncommutativity do not have a unitary S-matrix. Field
theories with only space noncommutativity are perturbatively
unitary. This can be understood from string theory, since
space noncommutative field theories describe a low energy
limit of string theory in a background magnetic field. On
the other hand, there is no regime in which space-time
noncommutative field theory is an appropriate description of
string theory. Whenever space-time noncommutative field
theory becomes relevant massive open string states cannot be
neglected. © 2000 Elsevier Science B.V.},
Key = {fds287688}
}

@article{fds287689,
Author = {Gomis, J and Mehen, T and Wise, MB},
Title = {Quantum Field Theories with Compact Noncommutative Extra
Dimensions},
Journal = {JHEP},
Volume = {8},
Number = {8 PART B},
Pages = {29},
Year = {2000},
Abstract = {We study field theories on spaces with additional compact
noncommutative dimensions. As an example, we study \phi^3 on
R^{1,3}\times T^{2}_\theta using perturbation theory. The
infrared divergences in the noncompact theory give rise to
unusual dynamics for the mode of \phi which is constant
along the torus. Correlation functions involving this mode
vanish. Moreover, we show that the spectrum of Kaluza-Klein
excitations can be very different from the analogous
commuting theory. There is an additional contribution to the
Kaluza-Klein mass formula that resembles the contribution of
winding states in string theory. We also consider the effect
of noncommutativity on the four dimensional Kaluza-Klein
excitations of a six dimensional gauge field.},
Key = {fds287689}
}

@article{fds287690,
Author = {Aharony, O and Gomis, J and Mehen, T},
Title = {On Theories with Lightlike Noncommutativity},
Journal = {JHEP},
Volume = {9},
Number = {9 PART A},
Pages = {23},
Year = {2000},
Abstract = {We show that field theories with light-like
noncommutativity, that is with $\theta^{0i}=-\theta^{1i}$,
are unitary quantum theories, and that they can be obtained
as decoupled field theory limits of string theory with
D-branes in a background NS-NS $B$ field. For general
noncommutativity parameters, we show that noncommutative
field theories which are unitary can be obtained as
decoupled field theory limits of string theory, while those
that are not unitary cannot be obtained from string theory
because massive open strings do not decouple. We study the
different theories with light-like noncommutativity which
arise from Type II D-branes. The decoupling limit of the
D4-brane seems to lead to a noncommutative field theory
deformation of the $(2,0)$ SCFT of M5-branes, while the
D5-brane case leads to a noncommutative variation of
little string theories''. We discuss the DLCQ description
of these theories.},
Key = {fds287690}
}

@article{fds287691,
Author = {Mehen, T and Wise, MB},
Title = {Generalized *-Products, Wilson Lines and the Solution of the
Seiberg-Witten Equations},
Journal = {JHEP},
Volume = {12},
Number = {12},
Pages = {8},
Year = {2000},
Abstract = {Higher order terms in the effective action of noncommutative
gauge theories exhibit generalizations of the *-product
(e.g. *' and *-3). These terms do not manifestly respect the
noncommutative gauge invariance of the tree level action. In
U(1) gauge theories, we note that these generalized
*-products occur in the expansion of some quantities that
are invariant under noncommutative gauge transformations,
but contain an infinite number of powers of the
noncommutative gauge field. One example is an open Wilson
line. Another is the expression for a commutative field
strength tensor in terms of the noncommutative gauge field.
Seiberg and Witten derived differential equations that
relate commutative and noncommutative gauge transformations,
gauge fields and field strengths. In the U(1) case we solve
these equations neglecting terms of fourth order in the
gauge field but keeping all orders in the noncommutative
parameter.},
Key = {fds287691}
}

@article{fds305713,
Author = {Gomis, J and Mehen, T and Wise, MB},
Title = {Quantum field theories with compact non-commutative extra
dimensions},
Journal = {Journal of High Energy Physics},
Volume = {4},
Number = {8 PART B},
Pages = {1-15},
Year = {2000},
Abstract = {We study field theories on spaces with additional compact
noncommutative dimensions. As an example, we study φ3 on
ℝ1,3xdouble-struck T signθ2 using perturbation theory.
The infrared divergences in the non-compact theory give rise
to unusual dynamics for the mode of φ which is constant
along the torus. Correlation functions involving this mode
vanish. Moreover, we show that the spectrum of Kaluza-Klein
excitations can be very different from the analogous
commuting theory. There is an additional contribution to the
Kaluza-Klein mass formula that resembles the contribution of
winding states in string theory. We also consider the effect
of noncommutativity on the four-dimensional Kaluza-Klein
excitations of a six-dimensional gauge field.},
Key = {fds305713}
}

@article{fds305714,
Author = {Gomis, J and Mehen, T and Rangamani, M and Kleban, M and Shenker,
S},
Title = {Non-commutative gauge dynamics from the string
worldsheet},
Journal = {Journal of High Energy Physics},
Volume = {4},
Number = {8 PART A},
Pages = {1-18},
Year = {2000},
Abstract = {We show how string theory can be used to reproduce the
one-loop two-point photon amplitude in non-commutative U(1)
gauge theory. Using a simple realization of the gauge theory
in bosonic string theory, we extract from a string cylinder
computation in the decoupling limit the exact one loop field
theory result. The result is obtained entirely from the
region of moduli space where massless open strings dominate.
Our computation indicates that the unusual IR/UV
singularities of non-commutative field theory do not come
from closed string modes in any simple way.},
Key = {fds305714}
}

@article{fds305715,
Author = {Mehen, T and Wise, MB},
Title = {Generalized *-products, Wilson lines and the solution of the
Seiberg-Witten equations},
Journal = {Journal of High Energy Physics},
Volume = {4},
Number = {12},
Pages = {XVII-9},
Year = {2000},
Abstract = {Higher order terms in the effective action of
non-commutative gauge theories exhibit generalizations of
the *-product (e.g. *′ and *3). These terms do not
manifestly respect the non-commutative gauge invariance of
the tree level action. In U(1) gauge theories, we note that
these generalized *-products occur in the expansion of some
quantities that are invariant under non-commutative gauge
transformations, but contain an infinite number of powers of
the non-commutative gauge field. One example is an open
Wilson line. Another is the expression for a commutative
field strength tensor Fab in terms of the non-commutative
gauge field Âa. Seiberg and Witten derived differential
equations that relate commutative and non-commutative gauge
transformations, gauge fields and field strengths. In the
U(1) case we solve these equations neglecting terms of
fourth order in Â but keeping all orders in the
non-commutative parameter θkl.},
Key = {fds305715}
}

@article{fds305716,
Author = {Aharony, O and Gomis, J and Mehen, T},
Title = {On theories with light-like noncommutativity},
Journal = {Journal of High Energy Physics},
Volume = {4},
Number = {9 PART A},
Pages = {XXXII-14},
Year = {2000},
Abstract = {We show that field theories with light-like
noncommutativity, that is with θ0i = θ1i, are unitary
quantum theories, and that they can be obtained as decoupled
field theory limits of string theory with D-branes in a
background NS-NS B-field. For general noncommutativity
parameters, we show that non-commutative field theories
which are unitary can be obtained as decoupled field theory
limits of string theory, while those that are not unitary
cannot be obtained from string theory because massive open
strings do not decouple. We study the different theories
with light-like noncommutativity which arise from type-II
D-branes. The decoupling limit of the D4-brane seems to lead
to a non-commutative field theory deformation of the (2,0)
SCFT of M5-branes, while the D5-brane case leads to a
non-commutative variation of "little string theories". We
discuss the DLCQ description of these theories.},
Key = {fds305716}
}

@article{fds305717,
Author = {Fleming, S and Mehen, T and Stewart, IW},
Title = {NN scattering 3S1-3D1
Journal = {Physical Review C - Nuclear Physics},
Volume = {61},
Number = {4},
Pages = {440051-440059},
Year = {2000},
url = {http://dx.doi.org/10.1103/PhysRevC.61.044005},
Abstract = {The 3S1-3D1 mixing angle for nucleon-nucleon scattering ∈1
is calculated to next-to-next-to-leading order in an
effective field theory with perturbative pions. Without
pions, the low energy theory fits the observed ∈1 well for
momenta less than∼50 MeV. Including pions perturbatively
significantly improves the agreement with data for momenta
up to ∼150 MeV with one less parameter. Furthermore, for
these momenta the accuracy of our calculation is similar to
an effective field theory calculation in which the pion is
treated nonperturbatively. This gives phenomenological
support for a perturbative treatment of pions in low energy
two-nucleon processes. We explain why it is necessary to
perform spin and isospin traces in d dimensions when
regulating divergences with dimensional regularization in
higher partial wave amplitudes.},
Doi = {10.1103/PhysRevC.61.044005},
Key = {fds305717}
}

@article{fds3910,
Author = {T. Mehen},
Title = {Leptoproduction of $J/\Psi$},
Booktitle = {Proceedings of the 29th International Conference on High
Energy Physics (ICHEP 98)},
Publisher = {World Scientific},
Editor = {A. Astbury and D. Axen and J. Robinson},
Year = {1999},
Abstract = {I review the status of the extraction of NRQCD color-octet
$J/\psi$ production matrix elements. Large theoretical
uncertainties in current extractions from hadroproduction
and photoproduction are emphasized. Leptoproduction of
$J/\psi$ is calculated within the NRQCD factorization
formalism. Color-octet contributions dominate the cross
section, allowing for a reliable extraction of $<{\cal O}_8^{J/\psi}(^1S_0)>$ and $<{\cal O}_8^{J/\psi}(^3P_0)>$. A
comparison with preliminary data from the H1 collaboration
shows that leading order color-octet mechanisms agree with
the measured total cross section for $Q^2 > 4m_c^2$, while
the color-singlet model underpredicts the cross section by a
factor of 5.},
Key = {fds3910}
}

@article{fds287680,
Author = {Mehen, T and Stewart, IW},
Title = {A momentum subtraction scheme for two-nucleon effective
field theory},
Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and
High-Energy Physics},
Volume = {445},
Number = {3-4},
Pages = {378-386},
Year = {1999},
Abstract = {We introduce a momentum subtraction scheme which obeys the
power counting of Kaplan, Savage, and Wise (KSW), developed
for systems with large scattering lengths, a. Unlike the
power divergence subtraction scheme, coupling constants in
this scheme obey the KSW scaling for μR &gt; 1/a. We
comment on the low-energy theorems derived by Cohen and
Hansen. We conclude that there is no obstruction to using
perturbative pions for momenta p &gt; mπ. © 1999 Elsevier
Key = {fds287680}
}

@article{fds287681,
Author = {Mehen, T and Stewart, IW},
Title = {Renormalization schemes and the range of two-nucleon
effective field theory},
Journal = {Physical Review C - Nuclear Physics},
Volume = {59},
Number = {5},
Pages = {2365-2383},
Year = {1999},
Abstract = {The off-shell momentum subtraction (OS) and power divergence
subtraction (PDS) renormalization schemes for the effective
field theory with nucleons and pions are investigated. We
explain in detail how the renormalization is implemented
using local counterterms. Fits to the NN scattering data are
performed in the 1S0 and 3S1 channels for different values
of μR. An error analysis indicates that the range of the
theory with perturbative pions is consistent with 500
MeV.},
Key = {fds287681}
}

@article{fds287683,
Author = {Mehen, T and Stewart, IW and Wise, MB},
Title = {Wigner symmetry in the limit of large scattering
lengths},
Journal = {Physical Review Letters},
Volume = {83},
Number = {5},
Pages = {931-934},
Year = {1999},
Abstract = {We note that, in the limit where the NN 1S0 and 3S1
scattering lengths, a(1S0) and a(3S1), go to infinity, the
leading terms in the effective field theory for strong NN
interactions are invariant under Wigner's SU(4) spin-isospin
pions on the S-wave NN scattering amplitudes vanish as
a(1S0) and a(3S1) go to infinity. The implications of Wigner
symmetry for NN → NN axion and γd → np are also
considered. © 1999 The American Physical
Society.},
Key = {fds287683}
}

@booklet{Fleming98,
Author = {Fleming, S and Mehen, T},
Title = {Photoproduction of h(c)},
Journal = {Physical Review D},
Volume = {5803},
Number = {3},
Pages = {art. no.-037503},
Year = {1998},
Month = {August},
ISSN = {0556-2821},
Abstract = {Using the NRQCD factorization formalism, we calculate the
total cross section for the photoproduction of h c mesons.
We include color-octet and color-singlet mechanisms as well
as next-to-leading order perturbative QCD corrections. The
theoretical prediction depends on two nonperturbative matrix
elements that are not well determined from existing data on
charmonium production. For reasonable values of these matrix
elements, the cross section is large enough that the h c may
be observable at the E831 experiment and at the DESY HERA
experiments.},
Key = {Fleming98}
}

@booklet{Mehen98,
Author = {Mehen, T},
Title = {Summing O(beta(n)(0)alpha(n+1)(s)) corrections to top quark
decays},
Journal = {Physics Letters B},
Volume = {417},
Number = {3-4},
Pages = {353-360},
Year = {1998},
Month = {January},
Abstract = {Order Î²0nÎ±sn+1 QCD corrections to top quark decays
into W+ and H+ bosons are computed to all orders in
perturbation theory. Predictions for the radiative
corrections to the top quark width are compared with the
estimates from BLM scale setting procedures. The results of
the summation are shown to greatly improve understanding of
higher order corrections in the limit mW, mH â†’ mt,
where the BLM scale setting method is known to fail.
Attempts to reduce nonperturbative error by substituting the
running mass for the pole mass in the expression for the
decay are shown to fail in the limit mW, mH â†’ mt
because of subtleties in the treatment of phase space. Â©
Key = {Mehen98}
}

@booklet{Fleming98a,
Author = {Fleming, S and Mehen, T},
Title = {Leptoproduction of J/ψ},
Journal = {Physical Review D - Particles, Fields, Gravitation and
Cosmology},
Volume = {57},
Number = {3},
Pages = {1846-1857},
Year = {1998},
Abstract = {We study leptoproduction of J/ψ at large Q2 within the
nonrelativistic QCD (NRQCD) factorization formalism. The
cross section is dominated by color-octet terms that are of
order αs. The color-singlet term, which is of order α2s,
is shown to make a small contribution to the total cross
section. We also calculate the tree diagrams for color-octet
production at order α2s in a region of phase space where
there is no leading color-octet contribution. We find that
in this regime the color-singlet contribution dominates. We
argue that nonperturbative corrections arising from
diffractive leptoproduction, higher twist effects, and
higher order terms in the NRQCD velocity expansion should be
suppressed as Q2 is increased. Therefore, the color-octet
matrix elements 〈script O signψ8(1S0)〉 and 〈script O
signψ8(3P0)〉 can be reliably extracted from this process.
Finally, we point out that an experimental measurement of
the polarization of leptoproduced J/ψ will provide an
excellent test of the NRQCD factorization
formalism.},
Key = {Fleming98a}
}

@article{fds305712,
Author = {Fleming, S and Mehen, T},
Title = {Photoproduction of hc},
Journal = {Physical Review D: Particles, Fields, Gravitation and
Cosmology},
Volume = {58},
Number = {3},
Pages = {0375031-0375034},
Year = {1998},
ISSN = {0556-2821},
url = {http://dx.doi.org/10.1103/PhysRevD.58.037503},
Abstract = {Using the NRQCD factorization formalism, we calculate the
total cross section for the photoproduction of hc mesons. We
include color-octet and color-singlet mechanisms as well as
next-to-leading order perturbative QCD corrections. The
theoretical prediction depends on two nonperturbative matrix
elements that are not well determined from existing data on
charmonium production. For reasonable values of these matrix
elements, the cross section is large enough that the hc may
be observable at the E831 experiment and at the DESY HERA
experiments.},
Doi = {10.1103/PhysRevD.58.037503},
Key = {fds305712}
}

@article{fds305711,
Author = {Mehen, T},
Title = {Summing O( β0nαsn+1)
corrections to top quark decays},
Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and
High-Energy Physics},
Volume = {417},
Number = {3-4},
Pages = {353-360},
Year = {1998},
url = {http://dx.doi.org/10.1016/S0370-2693(97)01348-8},
Abstract = {Order β0nαsn+1 QCD corrections to top quark decays into W+
and H+ bosons are computed to all orders in perturbation
theory. Predictions for the radiative corrections to the top
quark width are compared with the estimates from BLM scale
setting procedures. The results of the summation are shown
to greatly improve understanding of higher order corrections
in the limit mW, mH → mt, where the BLM scale setting
method is known to fail. Attempts to reduce nonperturbative
error by substituting the running mass for the pole mass in
the expression for the decay are shown to fail in the limit
mW, mH → mt because of subtleties in the treatment of
B.V.},
Doi = {10.1016/S0370-2693(97)01348-8},
Key = {fds305711}
}

@booklet{Mehen97,
Author = {Mehen, T},
Title = {Testing quarkonium production with photoproduced JlΨ+
γ},
Journal = {Physical Review D - Particles, Fields, Gravitation and
Cosmology},
Volume = {55},
Number = {7},
Pages = {4338-4343},
Year = {1997},
Abstract = {I compute the leading color-octet contributions to the
process γ+p→JlΨ+ γ(+Χ) within the nonrelativistic QCD
(NRQCD) factorization formalism. In the color-singlet model,
JlΨ+ γ can only be produced when the photon interacts
through its structure function, while the color-octet
mechanism allows for production of Jl Ψ+ γ via direct
photon-gluon fusion. Resolved photon processes can be
distinguished easily from direct photon processes by
examining the fraction of the incident photon energy carried
away by the Jl Ψ in the event. Therefore, this process
provides a conclusive test of the color-octet mechanism. Jl
Ψ+ γ production is particularly sensitive to the NRQCD
matrix element which figures prominently in the
fragmentation production of Jl Ψ at large p⊥ in hadron
colliders. I also examine the predictions of the color
evaporation model (CEM) of quarkonium production and find
that this process can easily discriminate between the NRQCD
factorization formalism and the CEM.},
Key = {Mehen97}
}

@booklet{Falk96,
Author = {Falk, AF and Mehen, T},
Title = {Excited heavy mesons beyond leading order in the heavy quark
expansion},
Journal = {Physical Review D - Particles, Fields, Gravitation and
Cosmology},
Volume = {53},
Number = {1},
Pages = {231-240},
Year = {1996},
Abstract = {We examine the decays of excited heavy mesons, including the
leading power corrections to the heavy quark limit. We find
a new and natural explanation for the large deviation of the
width of the D1 (2420) from the heavy quark symmetry
prediction. Our formalism leads to detailed predictions for
the properties of the excited bottom mesons, some of which
recently have been observed. Finally, we present a detailed
analysis of the effect of power corrections and finite meson
widths on the angular distributions which may be measured in
heavy meson decays.},
Key = {Falk96}
}

@booklet{Mehen96,
Author = {Mehen, T},
Title = {Scale setting in top quark decays},
Journal = {Physics Letters, Section B: Nuclear, Elementary Particle and
High-Energy Physics},
Volume = {382},
Number = {3},
Pages = {267-272},
Year = {1996},
url = {http://dx.doi.org/10.1016/0370-2693(96)00681-8},
Abstract = {We compute the O(β0α2s) QCD corrections to the Standard
Model decay t → W+ b as well as the non standard decay t
→ H+ b. We then use our results to compute the BLM scale
for these decays, and study the dependence of the BLM scale
on the mass of the boson in the decay. We find that the BLM
procedure gives extremely small scales when top decays into
heavy bosons. When we try to improve the BLM scale by
reexpressing rates as a functions of the top quark running
mass, we find the BLM scale exhibits unnatural dependence on
the boson mass, casting doubts on the applicability of the
BLM procedure to these processes.},
Doi = {10.1016/0370-2693(96)00681-8},
Key = {Mehen96}
}

%% Papers Accepted
@article{fds225631,
Author = {Thomas Mehen},
Title = {Exotic Quarkonium Spectroscopy: X(3872) Z(10610) Z(10650) in
Non-Relativistic Effective Theory},
Journal = {Conference Proeceedings for PhiPsi 2013, Rome, Italy,
September 11, 2013},
Year = {2013},
Key = {fds225631}
}

%% Preprints
@article{fds287641,
Author = {Kim, C and Mehen, T},
Title = {Octetonium at the LHC},
Journal = {Nuclear Physics, Section B: Proceedings Supplements},
Volume = {200-202},
Number = {1 C},
Pages = {179-182},
Year = {2010},
ISSN = {0920-5632},
url = {http://arXiv.org/abs/0909.5695},
Abstract = {Several models of new physics, such as grand unified
theories, Pati-Salam models, chiral color models, etc.,
predict the existence of an SU(2)L doublet of color-octet
scalars (COS). In the Manohar-Wise model, the Yukawa
couplings of the COS are assumed to be consistent with
Minimal Flavor Violation ensuring constraints from flavor
physics are satisfied even for relatively light scalars. In
this simple model we consider the production of color
singlet bound states of COS that we call octetonium.
Octetonium are mainly produced via gluon-gluon fusion and
have significant production cross sections at the LHC. They
can decay to pairs of gluons or electroweak gauge bosons. If
the masses of the octetonia are 1 TeV or less, these states
will be visible as resonances in γγ, W+W-, ZZ, and γZ. ©
2010 Elsevier B.V.},
Doi = {10.1016/j.nuclphysbps.2010.02.081},
Key = {fds287641}
}

@article{fds287640,
Author = {Fleming, S and Mehen, T},
Title = {X(3872) in effective field theory},
Journal = {AIP Conference Proceedings},
Volume = {1182},
Pages = {491-494},
Year = {2009},
ISSN = {0094-243X},
url = {http://arXiv.org/abs/0907.4142},
Abstract = {If the X(3872) resonance is a shallow boundstate of a the
charm mesons D0D̄*0 and D*0D̄0 it can be described by an
effective theory of nonrelativistic D mesons coupled to
nonrelativistic pions (X-EFT). In this talk, I give a brief
overview of the X(3872), followed by a short review of
X-EFT. I end my talk with results from calculations of the
the next-to-leading-order correction to the partial decay
width Γ[X→ D0D̄0π0], and the decay of X(3872) to P-wave
quarkonia. © 2009 American Institute of
Physics.},
Doi = {10.1063/1.3293853},
Key = {fds287640}
}