Effects of the restoration of U${}_A$(1) symmetry on pseudoscalar meson observables

Abstract

We investigate the restoration of chiral SU$(3)\otimes$SU$(3)$ and axial U${}_A$(1) symmetries, at finite temperature and density, in the framework of the three flavor Nambu-Jona-Lasinio model with anomaly. We implement a temperature (density) dependence of the anomaly coefficient motivated by lattice results for the topological susceptibility and we discuss the restoration of symmetries by analyzing the behavior of the mesonic chiral partners and of the mixing angles. The results indicate that the axial part of the symmetry is restored before the possible restoration of the full U(3)$\otimes$U(3) chiral symmetry can occur.

Comments: 4 pages, 1 figure. Contribution to Proc. Int. Europhysics Conf. on High Energy Physics (HEP2005), 21-27.7.2005, Lisboa, Portugal