On the chiral phase transition in hadronic matter

A qualitative analysis of the chiral phase transition in QCD with two massless quarks and nonzero baryon density is performed. It is assumed that, at zero baryonic density, rho = 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(rho) for rho > 0. At temperatures T-cont(rho) > T > T-ph(rho), there is a mixed phase consisting of the quark phase (stable) and the hadron phase (unstable). At the temperature T = T-cont(rho), the system experiences a continuous transition to the pure chirally symmetric phase. (C) 2004 MAIK Nauka / Interperiodica.