“…At vanishing quark masses, the chiral symmetries represent basic properties of the QCD Lagrangian, while at finite current quark masses, the chiral symmetry is explicitly broken [3] and the QCD phasediagram can be described by the first-principle LQCD [4,5] and various QCD-like approaches. In charactering SU (2) and SU(3), the Polyakov Nambu-Jona Lasinio (PNJL) model [6,7,8] and the Polyakov linear-sigma model (PLSM) [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23] have been implemented. The SU(4) Lagrangian has the same structure as that of SU(3) [9], for instance.…”