Transverse Energy per Charged Particle and Freeze-Out Criteria in Heavy-Ion Collisions

TL;DR

This paper investigates the behavior of transverse energy per charged particle in heavy-ion collisions, showing it stabilizes at high energies and relates to freeze-out conditions, with a model explaining these phenomena.

Contribution

It demonstrates that the hadron resonance gas model can qualitatively describe the energy dependence and centrality independence of E_T/N_ch in heavy-ion collisions.

Findings

E_T/N_ch increases with energy then stabilizes around 800 MeV.

The hadron resonance gas model qualitatively reproduces the observed trends.

E_T/N_ch relates to the chemical freeze-out criterion E/N ~ 1 GeV.

Abstract

In relativistic nucleus-nucleus collisions the transverse energy per charged particle, E_T/N_ch, increases rapidly with beam energy and remains approximately constant at about 800 MeV for beam energies from SPS to RHIC. It is shown that the hadron resonance gas model describes the energy dependence, as well as the lack of centrality dependence, qualitatively. The values of E_T/N_ch are related to the chemical freeze-out criterium E/N about 1 GeV valid for primordial hadrons.