Particle ratios at RHIC : effective hadron masses and chemical freeze-out

The measured particle ratios in central heavy-ion collisions at RHIC-BNL are investigated within a chemical and thermal equilibrium chiral SU(3) theta - omega approach. The commonly adopted noninteracting gas calculation
The measured particle ratios in central heavy-ion collisions at RHIC-BNL are investigated within a chemical and thermal equilibrium chiral SU(3) theta - omega approach. The commonly adopted noninteracting gas calculations yield temperatures close to or above the critical temperature for the chiral phase transition, but without taking into account any interactions. Contrary, the chiral SU(3) model predicts temperature and density dependent e ective hadron masses and e ective chemical potentials in the medium and a transition to a chirally restored phase at high temperatures or chemical potentials. Three di erent parametrizations of the model, which show di erent 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 di er considerably from those obtained in simple noninteracting gas calculations. In particular, the three models yield up to 35 MeV lower temperatures than the free gas approximation. The in-medium masses turn out di er up to 150 MeV from their vacuum values.
show moreshow less

Download full text files

Export metadata

  • Export Bibtex
  • Export RIS

Additional Services

    Share in Twitter Search Google Scholar
Metadaten
Author:Detlef Zschiesche, Stefan Schramm, Jürgen Schaffner-Bielich, Horst Stöcker, Walter Greiner
URN:urn:nbn:de:hebis:30-21165
Document Type:Preprint
Language:English
Date of Publication (online):2005/11/15
Year of first Publication:2002
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
Release Date:2005/11/15
Tag:chemical ; chiral SU(3) model; heavy-ion collisions ; thermal
Source:Phys.Lett.B547:7-14,2002. [nucl-th/0209022]
HeBIS PPN:185614612
Institutes:Physik
Dewey Decimal Classification:530 Physik
Sammlungen:Universitätspublikationen
Licence (German):License Logo Veröffentlichungsvertrag für Publikationen

$Rev: 11761 $