Screening masses of positive- and negative-parity hadron ground states, including those with strangeness

Using a symmetry-preserving treatment of a vector × vector contact interaction at nonzero temperature, we compute the screening masses of flavor-SU(3) ground-state J^P ¼ 0±, 1± mesons, and J^P ¼ 1=2±, 3=2± baryons. We find that all correlation channels allowed at T ¼ 0 persist when the temperature increases, even above the QCD phase transition temperature. The results for mesons qualitatively agree with those obtained from the contemporary lattice-regularized quantum chromodynamics simulations. One of the most remarkable features is that each parity-partner-pair degenerates when T > T_c, with T_c being the critical temperature. For each pair, the screening mass of the negative parity meson increases monotonously with temperature. In contrast, the screening mass of the meson with positive parity is almost invariant on the domain T ≲ T_c=2; when T gets close to T_c, it decreases but soon increases again and finally degenerates with its parity partner, which signals the restoration of chiral symmetry. We also find that the T-dependent behaviors of baryon screening masses are quite similar to those of the mesons. For baryons, the dynamical, nonpointlike diquark correlations play a crucial role in the screening mass evolution. We further calculate the evolution of the fraction of each kind of diquark within baryons respective to temperature. We observe that, at high temperatures, only J ¼ 0 scalar and pseudoscalar diquark correlations can survive within J^P ¼ 1=2± baryons.