The most abundantly produced hadron species in Si−Au collisions at the BNL-AGS (nucleons, pions, kaons, antikaons and hyperons) are shown to be in accord with emission from a thermal resonance gas source of temperature T ≃ 110 MeV and baryochemical potential µ B ≃ 540 MeV, corresponding to about 1/3 standard nuclear density. Our analysis takes the isopin asymmetry of the initial state fully into account.

The production of hadrons in Ni-Ni at the GSI laboratory is considered in a hadronic gas model with chemical equilibrium. Special attention is given to the abundance of strange particles which are treated using the exact conservation of strangeness. It is found that all the data can be described using a temperature T ϭ70Ϯ10 MeV and a baryon chemical potential B ϭ720Ϯ30 MeV. ͓S0556-2813͑98͒01706-3͔

We study chemical equilibration of quarks and gluons in central nuclear collisions at RHIC and LHC energies. The initial quark and gluon densities are taken from earlier studies as well as from recent perturbative QCD estimates and are then evolved via rate equations coupled to longitudinally boost-invariant fluid dynamics. We find that, for RHIC initial conditions, the lifetime of quark-gluon matter is too short in order for the quark and gluon number densities to chemically equilibrate prior to hadronization. In contrast, at LHC energies chemical equilibration is complete before the system hadronizes. Entropy production due to chemical equilibration can be as large as 30%.Comment: 30 pages (latex2e), 13 postscript figures, corrected one figure, further analysis performed, to be published in NP