QCD chiral condensate and pseudoscalar-meson properties in the nuclear medium at finite temperature

The pion and kaon properties in a nuclear medium at nonvanishing temperature as well as the quantum chromodynamics (QCD) chiral condensate in the presence of a magnetic field for various baryon densities are studied in the Nambu-Jona-Lasinio (NJL) model with the help of the proper-time regularization (PTR) scheme, simulating a QCD confinement. The density dependence of the quark mass in symmetric nuclear matter is obtained from the quark-meson coupling (QMC) model, which shares the same covariant feature with the NJL model, at quark level. We then analyze the QCD chiral condensates and dynamical masses for various baryon densities at finite temperature and magnetic field as well as the pion and kaon masses, pion and kaon weak-decay constants, pion- and kaon-quark coupling constants, and wave function renormalization factors for various baryon densities at finite temperature. We find that the QCD chiral condensates suppress with increasing temperature and baryon density and enhance under the presence of a magnetic field, which are consistent with other model predictions. Interestingly, the wave function renormalization factors for the pion and kaon increase with respect to temperature and reduce as the baryon density increases are found.

Automated summary

This study uses the NJL model and PTR scheme to investigate the properties of pions and kaons in a nuclear medium at nonvanishing temperature, as well as the relationship between QCD chiral condensates and baryon density. The findings show that QCD chiral condensates decrease with increasing temperature and baryon density, but increase in the presence of a magnetic field. Additionally, the wave function renormalization factors for pions and kaons increase with temperature, but decrease with increasing baryon density.