Thermal and Hadrochemical Equilibration in Nucleus-Nucleus Collisions at the SPS

Abstract

The currently available set of hadron abundances at the SPS for central S+Au(W,Pb) collisions is compared to predictions from a scenario assuming local thermal and hadrochemical equilibrium. The data are consistent with a freeze-out temperature T = 160-170 MeV. Spectra are consistent with this temperature range and a moderate transverse expansion. The freeze-out points at the AGS and SPS are found to be close to the phase boundary between a hadron gas and an ideal quark-gluon phase.

Comments: 14 pages + 3 figures. Paper replaced with version accepted for publication in Phys. Lett. B