Effective degrees of freedom of the Quark-Gluon Plasma

Abstract

The effective degrees of freedom of the Quark-Gluon Plasma are studied in the temperature range $\sim 1-2$ $ T_c$. Employing lattice results for the pressure and the energy density, we constrain the quasiparticle chiral invariant mass to be of order 200 MeV and the effective number of bosonic resonant states to be at most of order $\sim 10$. The chiral mass and the effective number of bosonic degrees of freedom decrease with increasing temperature and at $T \sim 2$ $T_c$ only quark and gluon quasiparticles survive. Some remarks regarding the role of the gluon condensation and the baryon number-strangeness correlation are also presented.