Susceptibilities and critical exponents within the Nambu--Jona-Lasinio model

TL;DR

This paper derives coupled equations for susceptibilities in the (2+1)-flavor Nambu--Jona-Lasinio model at finite temperature and chemical potential, analyzing their critical behavior near the QCD critical end point.

Contribution

It provides a strict derivation of susceptibility equations and analyzes their critical exponents near the QCD critical end point in SU(2) and SU(3) cases.

Findings

Susceptibilities exhibit similar critical behavior near the CEP.

Critical exponents align with theoretical predictions.

Results enhance understanding of phase transitions in QCD.

Abstract

In the mean field approximation of (2+1)-flavor Nambu--Jona-Lasinio model, we strictly derive several sets of coupled equations for the chiral susceptibility, the quark number susceptibility, etc. at finite temperature and quark chemical potential. The critical exponents of these susceptibilities in the vicinity of the QCD critical end point (CEP) are presented in SU(2) and SU(3) cases, respectively. It is found that these various susceptibilities share almost the same critical behavior near the CEP. The comparisons between the critical exponents for the order parameters and the theoretical predictions are also included.