Quark stars in the pure pseudo-Wigner phase

Abstract

In this paper, we take a different scenario of a pure quark star which is completely composed of quarks in the pseudo-Wigner phase. The equation of state (EOS) of deconfined quark stars is studied in the framework of the two-flavor NJL model, and the self-consistent mean field approximation is employed by introducing a parameter α combining the original Lagrangian and the Fierz-transformed Lagrangian, LR = (1 − α)L + αLF , to measure the weights of different interaction channels. We assume deconfinement phase transition happens along with the chiral phase transition. Thus, due to the lack of description of confinement in the NJL model, the vacuum pressure is set to confine quarks at low densities, which is the pressure corresponding to the critical point of chiral phase transition. We find that deconfined quark stars can reach over two-solar-mass, and the bag constant therefore shifts from (130 MeV) 4 to (150 MeV) 4 as α grows. In addition, the tidal deformability Λ is found to range from 253 to 482 along with the decrease of α, which satisfies the astronomical constraint of Λ < 800 for 1.4-solar-mass neutron stars.