Determination of the strength of the vector-type four-quark interaction in the entanglement Polyakov-loop extended Nambu-Jona-Lasinio model

We determine the strength Gv of the vector-type four-quark interaction in the entanglement Polyakov-loop extended Nambu-Jona-Lasinio (EPNJL) model from the results of recent lattice QCD simulations with two-flavor Wilson fermion. The quark number density is normalized by the Stefan-Boltzmann limit. The strength determined from the normalized quark number density at small baryon chemical potential μ and temperature T (which is higher than the pseudocritical temperature Tc of the deconfinement transition) is Gv=0.33Gs, where Gs is the strength of the scalar-type four-quark interaction. We explore the hadron-quark phase transition in the μ-T plane by using the two-phase model in which the quantum hadrodynamics model is used for the hadron phase and the EPNJL model is used for the quark phase. When Gv=0.33Gs, the critical baryon chemical potential of the transition at zero T is μc∼1.6GeV, which accounts for two-solar-mass measurements of neutron stars in the framework of the hadron-quark hybrid star model.