Effective interactions of hyperons and mass-radius relation of neutron stars

Abstract

We examine the role of hyperons in a neutron star based on the relativistic mean field approach. For nuclear matter below 1.5 times the normal nuclear density we constrain the model parameters by using the symmetric nuclear matter properties and theoretical investigations for neutron matter in the literature. We then extend the model to higher densities by including hyperons and isoscalar vector mesons that contain strangeness degree of freedom. We confirm that the $\varphi$ meson induces a $\Lambda$ repulsive force and hardens the equation of state. The hardening arising from the $\varphi$ meson compensates the softening from the existence of hyperons. The flavor SU(3) and spin-flavor SU(6) relations are examined as well. We found that the coupling constants fitted by neutron matter properties could yield high enough maximum mass of a neutron star and the obtained results satisfy both the mass and radius constraints. The onset of the hyperon direct Urca process in neutron stars is also investigated using our parametrization.

15 pages, REVTeX, revised version

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Cited by in corpus (5)

• New effective interactions for hypernuclei in density dependent relativistic mean field model
• The Role of Baryon Structure in Neutron Stars
• Higher mass limits of neutron stars from the equation of states in curved spacetime
• Effect of Dark matter and $\sigma$-cut potential on radial and non-radial oscillation modes in neutron stars
• Influence of hyperon-hyperon interaction on the properties of neutron stars