Correlations of conserved charges and QCD phase structure

TL;DR

This study investigates how correlations among conserved charges like baryon number, electric charge, and strangeness behave at finite temperature and chemical potential, revealing sensitive critical dynamics and non-monotonic energy dependence.

Contribution

It provides the first detailed calculation of higher-order conserved charge correlations using a 2+1 flavor effective theory with functional renormalization group methods.

Findings

Higher-order correlations are more sensitive to critical phenomena.

Non-monotonic energy dependence observed in specific baryon-strangeness correlations.

Strangeness neutrality and charge ratios are maintained throughout the analysis.

Abstract

Correlations of conserved charges, i.e., the baryon number, electric charge and the strangeness, have been calculated at finite temperature and chemical potential up to the fourth order. The calculations are done in a 2+1 flavor low energy effective theory, where quantum and thermal fluctuations are encoded through the evolution of flow equations within the functional renormalization group approach. Strangeness neutrality and a fixed ratio of the electric charge to the baryon number density are implemented throughout the computation. We find that higher-order correlations carry more sensitive critical dynamics in comparison to the quadratic ones, and a non-monotonic dependence of the fourth-order correlations between the baryon number and strangeness, $-\chi^{BS}_{31}/\chi^{S}_{2}$ and $\chi^{BS}_{22}/\chi^{S}_{2}$, on the collision energy is found.