Local equilibrium in heavy-ion collisions: Microscopic analysis of a central cell versus infinite matter

Abstract

We study the local equilibrium in the central $V=125 {\mathrm{fm}}^{3}$ cell in heavy-ion collisions at energies from 10.7A GeV (AGS) to 160A GeV (SPS) calculated in the microscopic transport model. In the present paper the hadron yields and energy spectra in the cell are compared with those of infinite nuclear matter, as calculated within the same model. The agreement between the spectra in the two systems is established for times $t>~10 \mathrm{fm}/c$ in the central cell. The cell results do not deviate noticeably from the infinite matter calculations with rising incident energy, in contrast to the apparent discrepancy with predictions of the statistical model (SM) of an ideal hadron gas. The entropy of this state is found to be very close to the maximum entropy, while hadron abundances and energy spectra differ significantly from those of the SM.