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

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.

Comments: 9 pages, 6 figures. Extension of arXiv:1510.07543