Restoration of chiral symmetry in quark models with effective one gluon exchange

The restoration of chiral symmetry at finite density and/or temperature is investigated in a wide class of one-gluon exchange models in the instantaneous approximation. If the effective quark interaction is less divergent than 1k2 for small momentum transfer k, we obtain Gaussian critical exponents for the chiral phase transitions at finite temperature and density, respectively. In the opposite case, for an interaction diverging faster than 1k2 in the infrared region, a qualitative different behavior of the quark self-energy near the critical Fermi momentum kc and the critical temperature Tc, respectively, is observed. In the first scenario, we find kc ≈ 2 ln 2 Tc, which compares well with recent data from QCD lattice simulations.