Chiral logarithmic sigma model at finite temperature and baryonic chemical potential

Abstract

A logarithmic potential is suggested to study the chiral phase transition, the critical temperature, and the meson masses at finite temperature and baryonic chemical potential. The logarithmic potential is based on some aspects of quantum chromodynamics (QCD) theory. The model has been solved in the mean-field approximation. We found that the behavior of meson masses takes a similar behavior as in the original sigma model and the Nambu–Jona-Lasinio model. The critical temperature is reduced in comparison with the original sigma model and it is in good agreement with recent lattice QCD results. The chiral phase transition is crossover in the case of chiral explicit breaking symmetry. The Goldstone boson theorem is studied, in which the meson mass is massive and pion mass is massless at lower temperatures. Our conclusions indicate to the present model successfully predicts the phase transition as well as in the original quark sigma model and the Nambu–Jona–Lasinio model. A new advantage of the present model, the critical temperature is in good agreement with lattice QCD results at zero chemical potential. A condition of spontaneous breaking symmetry is necessary to satisfy the Goldstone theorem in the chiral limit.