Spectrum of soft mode with thermal mass of quarks above critical temperature

Abstract

We study effects of a thermal-quark mass and Landau damping of quarks on the chiral phase transition and its soft modes at finite temperature. For this purpose we employ a simple model with the quark propagator obtained in the hard thermal loop approximation. We show that the chiral phase transition is second order even if quark have a finite thermal mass, and the thermal mass suppresses the chiral condensate. We argue that mesonic spectra have a large width due to scattering between gluons and quarks, and the van Hove singularity at threshold.