Interplay between [Delta] Particles and hyperons in neutron stars

Abstract

We analyze the effects of including [Delta](1232) isobars in an equation of state (EoS) forcold, [beta]-stable neutron star matter, employing Relativistic Nuclear Mean Field Theory. The selected EoS reproduces the properties of nuclear matter and finite nuclei, and also allows for the presence of hyperons in neutron stars having masses larger than 2M. We find that the composition and the structure of neutron stars are critically in uenced by the addition of the [delta]'s, an observation that allows us to constraint their interaction with the meson fields sigma and omega. Imposing that the EoS is stable and ensures the existence of 2M. neutron stars, as well as requiring agreement with data of [delta] excitation in nuclei, we find that, in the absence of other mechanisms stiffening the EoS at high densities, the interaction of the [delta]'s with the sigma and omega fields must be stronger than that of the nucleons.