We investigate the phase transitions characterized by deconfinement and restoration of chiral and axial symmetries,at finite temperature, in the framework of QCD inspired models. We compare the results obtained in the SU(2) Polyakov-Nambu-Jona-Lasinio model with anomaly and in its extended version, the Entangled Polyakov-Nambu-Jona-Lasinio model. In the last version, four-quark vertices with entanglement between the chiral condensate and the Polyakov loop are considered. The thermodynamics of the phase transitions, the meson spectrum, and in particular the convergence of axial and chiral partners, will be analyzed, as well as the topological susceptibility. We find that an explicit temperature dependence of the coupling vertices is necessary in both models in order to have effective restoration of the U$_A$(1) symmetry.
تحميل البحث