Effects of the Regularization on the Restoration of Chiral and Axial Symmetries

TL;DR

This paper investigates how a specific regularization method affects the restoration of chiral and axial symmetries at finite temperature within the SU(3) Nambu-Jona-Lasinio model, showing improved alignment with lattice results and highlighting the impact of high momentum quarks.

Contribution

It introduces a regularization approach that accounts for high momentum quarks at finite temperature, improving the prediction of symmetry restoration temperatures in the NJL model.

Findings

Critical temperature aligns better with lattice results.

Chiral and axial symmetries restore simultaneously at higher temperatures.

Regularization enhances the decrease of quark condensates, especially in the strange sector.

Abstract

The effects of a type of regularization for finite temperatures on the estoration of chiral and axial symmetries are investigated within the SU(3) Nambu-Jona-Lasinio model. The regularization consists in using an infinite cutoff in the integrals that are convergent at finite temperature, a procedure that allows one to take into account the effects of high momentum quarks at high temperatures. It is found that the critical temperature for the phase transition is closer to lattice results than the one obtained with the conventional regularization, and the restoration of chiral and axial symmetries, signaled by the behavior of several observables, occurs simultaneously and at a higher temperature. The restoration of the axial symmetry appears as a natural consequence of the full recovering of the chiral symmetry that was dynamically broken. By using an additional ansatz that simulates instanton suppression effects, by means of a convenient temperature dependence of the anomaly coefficient, we found that the restoration of U(2) symmetry is shifted to lower values, but the dominant effect at high temperatures comes from the new regularization that enhances the decrease of quark condensates, especially in the strange sector.