Approximate degeneracy of $J=1$ spatial correlators in high temperature QCD

TL;DR

This study investigates the degeneracy patterns of $J=1$ spatial correlators in high-temperature QCD, revealing emergent symmetries that unify different mesonic channels as temperature increases.

Contribution

It provides the first lattice QCD evidence for approximate degeneracy of all $J=1$ correlators at high temperatures, indicating emergent symmetries beyond conventional chiral symmetry.

Findings

Degeneracy of vector and axial-vector correlators above $T_c$

Approximate degeneracy of all $J=1$ correlators at high T

Evidence for emergent $SU(2)_{CS}$ and $SU(4)$ symmetries

Abstract

We study spatial isovector meson correlators in $N_f=2$ QCD with dynamical domain-wall fermions on $32^3\times 8$ lattices at temperatures $T=220-380$ MeV. We measure the correlators of spin-one ($J=1$) operators including vector, axial-vector, tensor and axial-tensor. Restoration of chiral $U(1)_A$ and $SU(2)_L \times SU(2)_R$ symmetries of QCD implies degeneracies in vector--axial-vector ($SU(2)_L \times SU(2)_R$) and tensor--axial-tensor ($U(1)_A$) pairs, which are indeed observed at temperatures above $T_c$. Moreover, we observe an approximate degeneracy of all $J=1$ correlators with increasing temperature. This approximate degeneracy suggests emergent $SU(2)_{CS}$ and $SU(4)$ symmeries at high temperatures, that mix left- and right-handed quarks.