Near-thermal equilibrium with Tsallis distributions in heavy-ion collisions

Abstract

Hadron yields in high-energy heavy-ion collisions have been fitted with thermal models using standard (extensive) statistical distributions. These models give insight into the freeze-out conditions at varying beam energies and lead to a systematic consistent picture of freeze-out conditions at all beam energies. In this paper, we investigate changes to this analysis when the statistical distributions are replaced by non-extensive Tsallis distributions for hadrons. We investigate the particle yields at SPS and RHIC energies and obtain better fits with smaller χ2 for the same hadron data, as applied earlier in the thermal fits for SPS energies but not for RHIC energies.