Critical endpoint in the Polyakov-loop extended NJL model

TL;DR

This paper investigates the phase structure and critical endpoint in an extended Polyakov-loop NJL model, revealing how specific interactions influence the phase transition temperatures and the location of the CEP.

Contribution

It introduces scalar eight-quark and vector four-quark interactions into the Polyakov-loop NJL model and analyzes their effects on the phase diagram and critical endpoint.

Findings

The  interaction shifts the CEP to higher temperature and lower chemical potential.

The vector interaction shifts the CEP in the opposite direction.

The  interaction aligns the chiral transition temperature with the deconfinement transition.

Abstract

The critical endpoint (CEP) and the phase structure are studied in the Polyakov-loop extended Nambu--Jona-Lasinio model in which the scalar type eight-quark (\sigma^4) interaction and the vector type four-quark interaction are newly added. The \sigma^4 interaction largely shifts the CEP toward higher temperature and lower chemical potential, while the vector type interaction does oppositely. At zero chemical potential, the \sigma^4 interaction moves the pseudo-critical temperature of the chiral phase transition to the vicinity of that of the deconfinement phase transition.