Symmetries of spatial meson correlators in high temperature QCD

Abstract

Based on a complete set of $J=0$ and $J=1$ spatial isovector correlation functions calculated with ${N}_{F}=2$ domain wall fermions we identify an intermediate temperature regime of $T\ensuremath{\sim}220--500\text{ }\text{ }\mathrm{MeV}$ ($1.2{T}_{c}--2.8{T}_{c}$), where chiral symmetry is restored but the correlators are not yet compatible with a simple free quark behavior. More specifically, in the temperature range $T\ensuremath{\sim}220--500\text{ }\text{ }\mathrm{MeV}$ we identify a multiplet structure of spatial correlators that suggests emergent $SU(2{)}_{CS}$ and $SU(4)$ symmetries, which are not symmetries of the free Dirac action. The symmetry breaking effects in this temperature range are less than 5%. Our results indicate that at these temperatures the chromomagnetic interaction is suppressed and the elementary degrees of freedom are chirally symmetric quarks bound into color-singlet objects by the chromoelectric component of the gluon field. At temperatures between 500 and 660 MeV the emergent $SU(2{)}_{CS}$ and $SU(4)$ symmetries disappear and one observes a smooth transition to the regime above $T\ensuremath{\sim}1\text{ }\text{ }\mathrm{GeV}$ where only chiral symmetries survive, which are finally compatible with quasifree quarks.