TY  - CONF
A1  - Bravina, Larissa
A1  - Brandstetter, Mathias
A1  - Gorenstein, Mark I.
A1  - Zabrodin, Eugene E.
A1  - Belkacem, Mohamed
A1  - Bleicher, Marcus
A1  - Bass, Steffen A.
A1  - Ernst, Christoph
A1  - Hofmann, M.
A1  - Soff, Sven
A1  - Stöcker, Horst
A1  - Greiner, Walter
T1  - Local thermal and chemical equilibration and the equation of state in relativistic heavy ion collisions
T2  - Talk given at SQM'98 conference, 20-24 July 1998, Padova, Italy, submitted to J. Phys. G
N2  - Thermodynamical variables and their time evolution are studied for central relativistic heavy ion collisions from 10.7 to 160 AGeV in the microscopic Ultrarelativistic Quantum Molecular Dynamics model (UrQMD). The UrQMD model exhibits drastic deviations from equilibrium during the early high density phase of the collision. Local thermal and chemical equilibration of the hadronic matter seems to be established only at later stages of the quasi-isentropic expansion in the central reaction cell with volume 125 fm 3. Baryon energy spectra in this cell are reproduced by Boltzmann distributions at all collision energies for t > 10 fm/c with a unique rapidly dropping temperature. At these times the equation of state has a simple form: P = (0.12 - 0.15) Epsilon. At SPS energies the strong deviation from chemical equilibrium is found for mesons, especially for pions, even at the late stage of the reaction. The final enhancement of pions is supported by experimental data.
Y1  - 1998
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/4803
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-6900
UR  - http://de.arxiv.org/abs/nucl-th/9810036
ER  -