Role of vector interaction and axial anomaly in the PNJL modeling of the QCD phase diagram

Effects of a-flavor singlet vector interaction in the Polyakov-Nambu-Jona-Lasinio (PNJL) Model are studied in combination with the axial U(1) breaking Kobayashi-Maskawa-'t Hooft interaction, using an improved, consistent cutoff scheme. We confirm that the first-order chiral phase transition at moderate baryon chemical potentials and its critical point, a generic feature of NJL-type models without vector coupling, disappear for sufficiently large vector coupling strength g(v). New results are presented concerning the curvature of the crossover boundary in the T-mu, plane close to mu = 0 and its dependence on g(v). (c) 2013 Elsevier B.V. All rights reserved.