The phase diagram in the SU(3) Nambu-Jona-Lasinio model with 't Hooft and eight-quark interactions

TL;DR

This paper investigates how eight-quark interactions influence the phase diagram of the SU(3) Nambu-Jona-Lasinio model, revealing shifts in the critical endpoint and clarifying the role of chiral symmetry breaking mechanisms.

Contribution

It demonstrates that increasing eight-quark interaction strength moves the phase transition endpoint towards lower chemical potentials and higher temperatures, linking it to chiral symmetry breaking.

Findings

The endpoint of the phase transition shifts with eight-quark interaction strength.

The connection between the endpoint location and chiral symmetry breaking is clarified.

Constraints on coupling strengths ensure groundstate stability.

Abstract

It is shown that the endpoint of the first order transition line which merges into a crossover regime in the phase diagram of the Nambu--Jona-Lasinio model, extended to include the six-quark 't Hooft and eight-quark interaction Lagrangians, is pushed towards vanishing chemical potential and higher temperatures with increasing strength of the OZI-violating eight-quark interactions. We clarify a connection between the location of the endpoint in the phase diagram and the mechanism of chiral symmetry breaking at the quark level. Constraints on the coupling strengths based on groundstate stability and physical considerations are explained.