Phase transition and thermodynamics of a hot and dense system in a scaled NJL model

The chiral phase transition of a hot and dense system of quarks is studied within a modified SU(3) NJL lagrangian that implements the QCD scale anomaly. The u- and s-quark condensates can feel or not the same chiral restoration depending on the considered region of the 3-dimension space T_c(\mu_uc,\mu_sc). The temperature behaviour of the pressure and of the energy and entropy densities of the u- and s-quark system is investigated. At high temperature, the non-vanishing bare s-quark mass only modifies slightly the usual behaviour associated with an ideal quark gas.