EQUILIBRATION OF MATTER IN RELATIVISTIC HEAVY-ION COLLISIONS

Abstract

The chemical and thermal equilibration in the central zone of heavy-ion collisions at energies from AGS to SPS is studied within the microscopic transport model. Yields and energy spectra obtained for the central cell in the reaction are compared to the predictions of the thermal statistical model. It is found that kinetic, thermal, and chemical equilibration of the expanding hadronic matter are nearly approached for the period of 10-18 fm/c. Within this time the matter in the cell expands almost isentropically. For the bombarding energies around 40 AGeV the system crosses the critical point in the T - μB plane predicted by lattice QCD calculations. The net strangeness in the central cell is negative (though small). The characteristic kink in the T - μB diagrams corresponding to beginning of the equilibrated phase is observed for all energies. The origin of this phenomenon deserves further investigation.