Chemical Freeze-out Parameters via a Non-perturbative QCD Approach

TL;DR

This paper uses a non-perturbative QCD approach to determine chemical freeze-out parameters by analyzing baryon susceptibility ratios, showing good agreement with experimental data and revealing non-monotonic behavior at lower energies.

Contribution

It introduces a Dyson-Schwinger equation-based method to extract freeze-out parameters and analyze susceptibility ratios, incorporating finite size effects for improved accuracy.

Findings

Excellent agreement with experimental data for  at .6 GeV and above.

Finite size effects are crucial for accurate freeze-out parameter determination.

The / ratio shows non-monotonic behavior at lower collision energies.

Abstract

By analyzing the calculated baryon number susceptibility ratios ${\chi_{1}^{B}}/{\chi_{2}^{B}}$ and ${\chi_{3}^{B}}/{\chi_{1}^{B}}$ in two-flavor system via the Dyson-Schwinger equation approach of QCD, we determine the chemical freeze-out temperature and baryon chemical potential in cases of both thermodynamic limit and finite size. We calculate the center-of-mass energy dependence of the ${\chi_{4}^{B}}/{\chi_{2}^{B}}\, (\kappa \sigma^{2})$ at the freeze-out line and find an excellent agreement with experimental data in $\sqrt{S_{NN}^{}} \geq 19.6\,$GeV region when taking into account the finite size effect. Our calculations indicate that the $\kappa \sigma^{2}$ exhibits a non-monotonic behavior in lower collision energy region.