TY  - JOUR
A1  - Bratkovskaya, Elena L.
A1  - Bleicher, Marcus
A1  - Cassing, Wolfgang
A1  - Leeuwen, Marco van
A1  - Reiter, Manuel
A1  - Soff, Sven
A1  - Stöcker, Horst
A1  - Weber, Henning
T1  - Strangeness dynamics in relativistic nucleus-nucleus collision
T2  - Progress in particle and nuclear physics
N2  - We investigate hadron production as well as transverse hadron spectra in nucleus-nucleus collisions from 2 A.GeV to 21.3 A.TeV within two independent transport approaches (UrQMD and HSD) that are based on quark, diquark, string and hadronic degrees of freedom. The comparison to experimental data demonstrates that both approaches agree quite well with each other and with the experimental data on hadron production. The enhancement of pion production in central Au+Au (Pb+Pb) collisions relative to scaled pp collisions (the 'kink') is well described by both approaches without involving any phase transition. However, the maximum in the K+/Pi+ ratio at 20 to 30 A.GeV (the 'horn') is missed by ~ 40%. A comparison to the transverse mass spectra from pp and C+C (or Si+Si) reactions shows the reliability of the transport models for light systems. For central Au+Au (Pb+Pb) collisions at bombarding energies above ~ 5 A.GeV, however, the measured K +/- m-theta-spectra have a larger inverse slope parameter than expected from the calculations. The approximately constant slope of K+/-spectra at SPS (the 'step') is not reproduced either. Thus the pressure generated by hadronic interactions in the transport models above ~ 5 A.GeV is lower than observed in the experimental data. This finding suggests that the additional pressure - as expected from lattice QCD calculations at finite quark chemical potential and temperature - might be generated by strong interactions in the early pre-hadronic/partonic phase of central Au+Au (Pb+Pb) collisions.
KW  - Relativistic heavy-ion collisions
KW  - Particle and resonance production
KW  - Meson production
KW  - Quark gluon plasma
Y1  - 2005
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/4814
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-6793
SN  - 0146-6410
N1  - © 2004 Elsevier B.V. All rights reserved.
VL  - 53
IS  - 1
SP  - 225
EP  - 237
PB  - Pergamon Press
CY  - Oxford [u. a.] ; Frankfurt, M.
ER  -