The quarkyonic matter state of neutron stars

Abstract

This work extends our previous study of isospin symmetric quarkyonic matter to quarkyonic neutron matter which might be relevant to the inner cores of neutron stars. The vector-isovector ρ mesons are introduced to the model mainly to account for isospin density interactions, just like ω meson for baryon density interactions. The modified Lagrangian still preserves approximate chiral symmetry which could be significantly broken at lower density. And new free parameters are fixed by adopting the experimental constraints on the symmetry energy and its slope at saturation density. Eventually, the pressure and mass-radius relation are explored in advance for the quarkyonic neutron stars: while the former is well consistent with experimental restrictions, the latter is unable to reproduce the observed two solar mass of PSR J0740+6620.