Symmetry of screening masses of mesons in two-flavor lattice QCD at high temperatures

TL;DR

This study analyzes mesonic correlation functions in two-flavor lattice QCD at high temperatures to understand symmetry restoration and compare with perturbative predictions, using advanced fermion actions for precise results.

Contribution

It provides detailed lattice QCD results on mesonic screening masses at high temperatures with controlled chiral symmetry, exploring symmetry restoration and deviations from perturbative behavior.

Findings

Chiral symmetry is approximately restored above the critical temperature.

Screening masses approach perturbative predictions at high temperatures.

Evidence of symmetry enhancements beyond chiral symmetry.

Abstract

We investigate spatial two-point correlation functions of mesonic operators in two-flavor lattice QCD at high temperatures. The simulated temperatures over the range $T \in [147, 330]$ MeV, where the critical temperature is estimated around 165 MeV. To ensure a good control of the chiral symmetry we employ the M\"obius domain-wall fermion action for two degenerate flavors of quarks. With a lattice cut off $a^{-1}\sim 2.6$ GeV, the residual mass is reduced to 0.14 MeV. With the energy spectrum obtained from the screening mass at incremental values of the temperature range, we examine the $SU(2)_L\times SU(2)_R$ chiral symmetry, the anomalous axial $U(1)$ as well as an enhanced symmetry which exchanges the spin degrees of freedom. We also study how the data approaches the perturbative prediction given by twice the Matsubara frequency of free quarks.