Flavour and Energy Dependence of Chemical Freeze-out Temperatures in Relativistic Heavy Ion Collisions from RHIC-BES to LHC Energies

TL;DR

This study analyzes chemical freeze-out temperatures in heavy ion collisions across a wide energy range, revealing flavor-dependent freeze-out temperatures near the QCD crossover region using a thermal model approach.

Contribution

It introduces a flavor-dependent chemical freeze-out model based on particle yields from RHIC and LHC energies, highlighting differences between light and strange quark freeze-out temperatures.

Findings

Light flavor freeze-out temperature T_L ≈ 150 MeV

Strange flavor freeze-out temperature T_S ≈ 165 MeV

Evidence for flavor dependence near QCD crossover

Abstract

We present calculations of the chemical freeze-out temperature (T_ch) based on particle yields from STAR and ALICE measured at collision energies ranging from sqrt{s_{NN}} = 11.5 GeV to 5.02 TeV. Employing the Grand Canonical Ensemble approach using the Thermal-FIST Hadron Resonance Gas model package, we show evidence for a flavour-dependent chemical freeze-out in the crossover region of the QCD phase diagram. At a vanishing baryochemical potential, we calculate light and strange flavour freeze-out temperatures T_L = 150.2 +- 2.6 MeV and T_S = 165.1 +- 2.7 MeV, respectively.