Excluded-volume model for quarkyonic matter. II. Three-flavor shell-like distribution of baryons in phase space

Abstract

We extend the excluded volume model of iso-spin symmetric two-flavor dense Quarkyonic matter including strange baryons and quarks and address its implications for neutron stars. The effective size of baryons are defined from the diverging hard-core potentials in the short interdistance regime. Around the hard-core density, the repulsive core between baryons at short-distances leads to a saturation in the number density of baryons and genarates the perturbative quarks from the lower phase space which leads to the shell-like distribution of baryons by Pauli's exclusion principle. The strange quark Fermi sea always appears in the high densities but $\Lambda$ hyperon shell only appears when the effective size of $\Lambda$ hyperon is smaller than the effective size of nucleons. We find that the pressure of strange quarkyonic matter can be large enough to support neutron stars with two-time solar mass and can have a large sound speed $c_s^2 \simeq 0.7$. The fraction of the baryon number carried by perturbative quarks is about 30% at the inner core of most massive neutron stars.