TY  - JOUR
A1  - Zschiesche, Detlef
A1  - Zeeb, Gebhard
A1  - Paech, Kerstin
A1  - Stöcker, Horst
A1  - Schramm, Stefan
T1  - Particle ratios from AGS to RHIC in an interacting hadronic model
T2  - Journal of Physics G: Nuclear and Particle Physics
N2  - Abstract: The measured particle ratios in central heavy-ion collisions at RHIC-BNL are investigated within a chemical and thermal equilibrium chiral SU(3) Ã É approach. The commonly adopted non-interacting gas calculations yield temperatures close to or above the critical temperature for the chiral phase transition, but without taking into account any interactions. In contrast, the chiral SU(3) model predicts temperature and density dependent effective hadron masses and effective chemical potentials in the medium and a transition to a chirally restored phase at high temperatures or chemical potentials. Three different parametrizations of the model, which show different types of phase transition behaviour, are investigated. We show that if a chiral phase transition occured in those collisions, freezing of the relative hadron abundances in the symmetric phase is excluded by the data. Therefore, either very rapid chemical equilibration must occur in the broken phase, or the measured hadron ratios are the outcome of the dynamical symmetry breaking. Furthermore, the extracted chemical freeze-out parameters differ considerably from those obtained in simple non-interacting gas calculations. In particular, the three models yield up to 35 MeV lower temperatures than the free gas approximation. The inmedium masses turn out to differ up to 150 MeV from their vacuum values.
KW  - Partikel
KW  - Kollisionen des schweren Ions
KW  - Gleichgewicht
KW  - hadronic
KW  - particle ratios
KW  - heavy-ion collisions
KW  - equilibrium
KW  - hadronic
Y1  - 2003
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3316
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-20728
VL  - 30.2004
SP  - S381
EP  - S391
ER  -