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

TL;DR

This paper uses a non-perturbative QCD approach to analyze baryon susceptibility ratios, determining freeze-out parameters and predicting nonmonotonic behavior in higher-order fluctuations, aligning well with experimental data.

Contribution

It introduces a Dyson-Schwinger equation-based method to extract chemical freeze-out parameters and predicts nonmonotonic fluctuations in baryon number susceptibilities.

Findings

Excellent agreement with experimental data for $\kappa \sigma^2$ when including finite size effects.

Nonmonotonic behavior of $\kappa \sigma^2$ in low-energy collisions.

Predicted nonmonotonic energy dependence of $\chi_6^B/\chi_2^B$.

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 when taking into account the finite size effect. Our calculations indicate that the $\kappa \sigma^{2}$ exhibits a nonmonotonic behavior in lower collision energy region. We also predict that the collision energy dependence of ${\chi_{6}^{B}}/{\chi_{2}^{B}}$ is nonmonotonic.