Influence of the σ-ω meson interaction on neutron star matter

Relativistic mean field theory with nonlinear scalar self-interaction and isoscalar scalar-vector cross-interaction is used to study the properties of neutron star matter in β equilibrium with and without hyperons. The influence of σ-ω meson cross-interaction on the properties of neutron star matter and the mass-radius relation of neutron stars is examined with attractive and repulsive Σ potential, respectively. The calculated result indicates that the cross-interaction softens the equation of state (EOS) of nuclear (hadronic) matter and reduces the maximum mass of neutron stars. It also decreases the densities for hyperonization to occur and lowers the center density of neutron stars. The increase of the cross-interaction strength enhances the softening effect of hyperons on the EOS. Meanwhile the repulsive Σ potential stiffens slightly the EOS and influences obviously the composition of neutron star matter