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

Abstract

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–ʼt 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 gv. New results are presented concerning the curvature of the crossover boundary in the T–μ plane close to μ=0 and its dependence on gv.