Polyakov SU(3) extended linear-sigma model: Sixteen mesonic states in chiral phase structure

Abstract

In the mean field approximation, the derivative of the grand potential, nonstrange and strange condensates, and the deconfinement phase transition in a thermal and dense hadronic medium are verified in the SU(3) Polyakov linear-sigma model (PLSM). The chiral condensates sigma(x) and sigma(y) are analyzed with the goal of determining the chiral phase transition. The temperature and density dependences of the chiral mesonic phase structures are taken as free parameters and fitted experimentally. They are classified according to the scalar meson nonets: (pseudo) scalar and (axial) vector. For the deconfinement phase transition, the effective Polyakov-loop potentials phi and phi* are implemented. The in-medium effects on the masses of sixteen mesonic states are investigated. The results are presented for two different forms for the effective Polyakov-loop potential and compared with other models, which include and exclude the anomalous terms. It is found that the Polyakov-loop potential has considerable effects on the chiral phase transition so that the restoration of the chiral symmetry breaking becomes sharper and faster. Assuming that the Matsubara frequencies contribute to the meson masses, we have normalized all mesonic states with respect to the lowest frequency. By doing this, we characterize temperatures and chemical potentials at which the different meson states dissolve to free quarks. Different dissolving temperatures and chemical potentials are estimated. The different meson states survive the typically averaged QCD phase boundary, which is defined by the QCD critical temperatures at varying chemical potentials. The thermal behavior of all meson masses has been investigated in the large-N-c limit. It is found that, at high T, the scalar meson masses are T independent (except pi and sigma). For the pseudoscalar meson masses, the large-N-c limit unifies the T dependences of the various states into a universal bundle. The same is also observed for axial and axial-vector meson masses.