New insight about the effective restoration of UA (1) symmetry

Abstract

The effective restoration of the UA(1) symmetry is revisited by implementing the functional renormalization group approach combined with the 2+1 flavor Polyakov-loop quark-meson model. A temperature-dependent 't Hooft term is taken to imitate the restoration of the UA(1) symmetry. Order parameters, meson spectrum and mixing angles, especially the pressure, the entropy density, and the speed of sound of the system are calculated to explore the effects of different UA(1) symmetry restoration patterns. We show then that the temperature for the restoration of the UA(1) symmetry is much higher than that for the chiral symmetry SUA(3).