Hybrid neutron stars in the Thomas-Fermi theory

Abstract

The baryon-quark phase transition is studied for the equation of state (EOS) of neutron star (NS) matter. The Thomas-Fermi (TF) approximation is employed in a semiclassical mean-field (MF) model for the EOS of baryonic matter including hyperons. The EOS of quark matter is also extracted from the Nambu–Jona-Lasinio (NJL) model. The phase transition from baryons to quarks is considered in the NS structure under the Maxwell and Gibbs constructions. Our findings for the maximum mass of NSs, as compared with the almost 2M pulsars J1614 − 2230 and J0348 + 0432, indicate that a region of baryon-quark mixed phase can exist in the inner core of NSs, while the existence of a pure phase is not allowed.