Screening properties of quark–anti-quark correlators in deconfined medium

We present results for the inverse screening lengths (i.e. the screening masses) of quark–antiquark systems belonging to different spin-parity channels. The results are obtained from lattice QCD simulations of 2 + 1 flavors of dynamical quarks with masses that correspond to realistic pion and almost physical kaon masses at zero temperature. For the light quarks our study shows that the screening masses in the pseudo-scalar and the isovector scalar channels do not become equal at the chiral crossover of QCD. This indicate that the effective restoration of the axial symmetry does not coincide with the chiral crossover of QCD. Moreover, even in the limit of zero lattice spacing the screening masses in the pseudo-scalar and the vector channels do not become degenerate at a moderately high temperature of 420 MeV. For the charm quarks we found that the screening masses in the pseudo-scalar and the vector channels remain almost equal to their zero temperature masses for temperatures less than 300 MeV. We also present a more detailed study of the screening masses in the charm quark sector by employing periodic boundary conditions along the temporal direction.