Strange freezeout

TL;DR

This paper proposes a two-stage freezeout model for hadrons in heavy-ion collisions, which better fits experimental data and suggests potential links between freezeout dynamics and QCD phase transitions.

Contribution

It introduces a simple two-freezeout model that improves data description over single freezeout models and explores implications for QCD phase transitions.

Findings

Two freezeout points better fit the data than one.

Constraints on late-stage fireball evolution are identified.

Possible influence of QCD phase transitions on particle yields.

Abstract

We argue that known systematics of hadron cross sections may cause different particles to freeze out of the fireball produced in heavy-ion collisions at different times. We find that a simple model with two freezeout points is a better description of data than that with a single freezeout, while still remaining predictive. The resulting fits seem to present constraints on the late stage evolution of the fireball, including the tantalizing possibility that the QCD chiral transition influences the yields at sqrt(S)=2700 GeV and the QCD critical point those at sqrt(S)=17.3 GeV.