On the chiral phase transition in hadronic matter

Abstract

A qualitative analysis of the chiral phase transition in QCD with two massless quarks and non--zero baryon density is performed. It is assumed that at zero baryonic density, ρ=0, the temperature phase transition is of the second order. Due to a specific power dependence of baryon masses on the chiral condensate the phase transition becomes of the first order at the temperature T=T_{ph}(ρ) for ρ>0. At temperatures T_{cont}(ρ) > T > T_{ph}(ρ) there is a mixed phase consisting of the quark phase (stable) and the hadron phase (unstable). At the temperature T = T_{cont}(ρ) the system experiences a continuous transition to the pure chirally symmetric phase.