Taste symmetry breaking at finite temperature

TL;DR

This paper investigates how taste symmetry breaking in lattice QCD varies with temperature, analyzing screening masses and meson channels to understand chiral symmetry restoration effects.

Contribution

It provides a detailed study of taste symmetry violation at finite temperature using dynamical lattice configurations and explores the temperature dependence of various mesonic channels and decay constants.

Findings

Taste violation agrees with chiral perturbation theory below transition.

Taste splitting persists above transition with temperature-dependent slope.

The pion decay constant decreases with temperature, indicating chiral symmetry restoration.

Abstract

The breaking of the taste symmetry is studied in the temperature range between 140 MeV to 550 MeV. In order to investigate this violation we have calculated the screening masses of the various taste states fitting the exponential decay of the spatial correlators. The computation has been performed using dynamical Nf = 2+1 gauge field configurations generated with the p4 staggered action along the Line of Constant Physics (LCP) defined by a pion mass $m_\pi$ of approximately 220 MeV and the kaon mass $m_K$ equals 500 MeV. For temperatures below the transition an agreement with the predictions of the staggered chiral perturbation theory has been found and no temperature effect can be observed on the taste violation. Above the transition the taste splitting still shows an O(a^2) behavior but with a temperature dependent slope. In addition to the analysis done for the pion multiplet we have performed an analogous computation for the light-strange and strange mesons and also looked at the scalar, vector and axial vector channels to understand how the multiplets split at finite temperature. Finally the temperature dependence of the pion decay constant $f_{\pi}$ is investigated to get further information about the chiral symmetry restoration.