J. Cleymans

Comparison of Chemical Freeze-Out Criteria in Heavy-Ion Collisions

One of the most remarkable results to emerge from heavy-ion collisions over the past two decades is the striking regularity shown by particle yields at all energies. This has led to several very successful proposals describing particle yields over a very wide range of beam energies, reaching from

Chemical and thermal freezeout parameters from 1-A/GeV to 200-A/GeV

1A

Features of particle multiplicities and strangeness production in central heavy ion collisions between 1 . 7 A and 1 5 8 A GeV / c

GeV up to 200A GeV, using only one or two parameters. A systematic comparison of these proposals is presented here. The conditions of fixed energy per particle, baryon+anti-baryon density, normalized entropy density as well as percolation model are investigated. The results are compared with the most recent chemical freeze-out parameters obtained in the thermal-statistical analysis of particle yields. The sensitivity and dependence of the results on parameters is analyzed and discussed. It is shown that in the energy range above the top energy of the BNL Alternating Gradient Synchrotron within present accuracies, all chemical freeze-out criteria give a fairly good description of the particle yields. However, the low energy heavy-ion data favor the constant energy per particle as a unified condition of chemical particle freeze-out. This condition also shows the weakest sensitivity on model assumptions and parameters.

THERMUS—A thermal model package for ROOT ✩

The present knowledge about hadrons produced in relativistic heavy ion collisions is compatible with chemical freeze-out happening when the energy density divided by the particle density reaches the value of 1 GeV. This observation is used to determine the energy dependence of the chemical freeze-out parameters

Hadron production in ultra-relativistic nuclear collisions: Quarkyonic matter and a triple point in the phase diagram of QCD

{T}_{\mathrm{ch}}

The Tsallis distribution in proton?proton collisions at

and

\sqrt{s}

{\ensuremath{\mu}}_{B}^{\mathrm{ch}}

= 0.9 TeV at the LHC

for beam energies varying between 1 and

Thermal hadron production in high energy heavy ion collisions

200A

Influence of impact parameter on thermal description of relativistic heavy ion collisions at (1-2)A GeV

GeV. The consequences of this energy dependence are studied for various particle ratios. Predictions for particle ratios at beam energy