Publications [#245365] of Steffen A. Bass

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Papers Published
  1. Bravina, LV; Gorenstein, MI; Zabrodin, EE; Bass, SA; Belkacem, M; Bleicher, M; Brandstetter, M; Hofmann, M; Soff, S; Spieles, C; Weber, H; Stöckerand, H; Greiner, W, Equilibrium and non-equilibrium effects in nucleus - Nucleus collisions, Physics Letters B, vol. 459 no. 4 (1999), pp. 660-666 .

    Abstract:
    Local thermal and chemical equilibration is studied for central A + A collisions at 10.7-160 AGeV in the Ultrarelativistic Quantum Molecular Dynamics model (UrQMD). The UrQMD mode exhibits strong deviations from local equilibrium at the high density hadron-string phase formed during the early stage of the collision. Equilibration of the hadron-resonance matter is established in the central cäl of volume V = 125 fmat later stages, t > 10 fm/c, of the resulting quasi-isentropic expansion. The thermodynamical functions in the cell and their time evolution are presented. Deviations of the UrQMD quasi-equilibrium state from the statistical mechanics equilibrium are found. They increase with energy per baryon and lead to a strong enhancement of the pion number density as compared to statistical mechanics estimates at SPS energies. ©1999 Published by Elsevier Science B.V. All rights reserved.