Phase diagram and thermodynamics of the Polyakov linear sigma model with three quark flavors

Abstract

The phase diagram at finite temperature and density is investigated in the framework of the Polyakov linear sigma model (PLSM) with three light quark flavors in the mean field approximation. It is found that in the PLSM, the three phase transitions, i.e, the chiral restoration of $u,d$ quarks, the chiral restoration of $s$ quark, and the deconfinement phase transition are independent. There exists two-flavor quarkyonic phase at low density and three-flavor quarkyonic phase at high density. The critical end point (CEP) which separating the crossover from the first-order line in the PLSM model is located at$(T_E, \mu_E)=(188 \mathrm{MeV},139.5 \mathrm{MeV})$. In the transition region the thermodynamic properties and bulk viscosity over entropy density ratio $\zeta/s$ are also discussed in the PLSM.