Quark matter in an SU(3) Nambu–Jona-Lasinio model with two types of vector interactions

Abstract

We investigate the properties of asymmetric quark matter and strange quark matter in the framework of the SU(3) Nambu--Jona-Lasinio (NJL) model with two types of vector interactions: (1) the flavor-dependent repulsion among different flavors of quarks with the coupling constant ${G}_{V}$, and (2) the universal repulsion and the vector-isovector interaction among different flavors of quarks with the coupling constants ${g}_{V}$ and ${G}_{IV}$. Using these two types of vector interactions in the NJL model, we study the quark symmetry energy in asymmetric quark matter, the constituent quark mass, the quark fraction, the equation of state in strange quark matter, the maximum mass of a quark star, and the properties of the QCD phase diagram. We find that including the two types of vector interactions in the SU(3) NJL model can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark stars. In particular, our results indicate that we can describe PSR $\mathrm{J}1614\ensuremath{-}2230$ and PSR $\mathrm{J}0348+0432$ as quark stars by considering the universal repulsion and the vector-isovector interaction among quark matter in the SU(3) NJL model.