OZI violating eight-quark interactions as a thermometer for chiral transitions

TL;DR

This paper investigates how OZI violating eight-quark interactions influence the chiral transition temperature in QCD-like models, showing they can serve as a thermometer for the nature of the transition, whether crossover or first order.

Contribution

It extends previous work to realistic quark masses and demonstrates the role of eight-quark interactions in determining the chiral transition's nature and temperature.

Findings

Eight-quark interactions lower the chiral transition temperature.

Depending on their strength, the transition can be a rapid crossover or first order.

Meson spectra at zero temperature are largely unaffected except for specific scalar channels.

Abstract

This work is a follow-up of our recent observation that in the SU(3) flavor limit with vanishing current quark masses the temperature for the chiral transition is substantially reduced by adding eight-quark interactions to the Nambu - Jona-Lasinio Lagrangian with U_A(1) breaking. Here we generalize the case to realistic light and strange quark masses and confirm our prior result. Additionally, we demonstrate that depending on the strength of OZI violating eight-quark interactions, the system undergoes either a rapid crossover or a first order phase transition. The meson mass spectra of the low lying pseudoscalars and scalars at T=0 are not sensitive to the difference in the parameter settings that correspond to these two alternatives, except for the singlet-octet mixing scalar channels, mainly the sigma meson.