Aspects of chiral symmetry in QCD at T=128 MeV

We investigate several aspects of chiral symmetry in QCD at a temperature of T = 128 MeV. The study is based on a 24 x 963 lattice-QCD ensemble with O(a)-improved Wilson quarks and physical up, down and strange quark masses. The pion quasiparticle turns out to be significantly lighter than the zerotemperature pion mass, even though the corresponding static correlation length is shorter. We perform a quantitative comparison of our findings to predictions of chiral perturbation theory. Among several order parameters for chiral symmetry restoration, we compute the difference of the vector- and axial-vector timedependent correlators and find it to be reduced by a factor similar to 2/3 as compared to its vacuum counterpart.

Automated summary

We investigate various aspects of chiral symmetry in QCD at T = 128 MeV using a 24 x 963 lattice-QCD ensemble with O(a)-improved Wilson quarks and physical up, down, and strange quark masses. The pion quasiparticle is found to be significantly lighter than the zero-temperature pion mass, despite having a shorter static correlation length. Our findings are quantitatively compared to predictions of chiral perturbation theory. Among several order parameters for chiral symmetry restoration, we compute the reduction of the difference between the vector- and axial-vector time-dependent correlators, which is found to be about two-thirds compared to its vacuum counterpart.