The critical surface of the SU(3)_L x SU(3)_R chiral quark model at   non-zero baryon density
  The boundary of the first order chiral phase transition region is studied in the m_pi-m_K-mu_B space using the one-loop optimized perturbation theory for the resummation of the perturbative series. Chiral perturbation theory for mesons and baryons is used for the T=0 parametrization of the model. The surface of second order transition points bends with increasing mu_B towards the physical point of the m_pi-m_K mass plane allowing for the existence of the critical end point in the mu_B-T plane at the physical point. The location and scaling region of the CEP is explored. 
P. Kovacs, Zs. Szep