Effects of an isovector scalar meson on the equation of state of dense matter within a relativistic mean field model

The effects of the isovector scalar δ-meson field on the properties of finite nuclei, infinite nuclear matter, and neutron stars are investigated within a relativistic mean field (RMF) model which includes nonlinear couplings. Several parameter sets (SRVs) are generated to asses the influence of the δ meson on the properties of neutron stars. These parametrizations correspond to different values of the coupling constant of the δ meson to nucleons, with remaining ones calibrated to yield finite nuclei and infinite nuclear matter properties consistent with the available experimental data. It is observed that, to fit the properties of finite nuclei and infinite nuclear matter, a stronger coupling between the isovector vector ρ meson and nucleons is required in the presence of a δ field. Furthermore, the δ meson is found to affect the radius of the canonical neutron star significantly. The value of dimensionless tidal deformability, Λ , for the canonical neutron star also satisfies the constraints from the waveform model analysis of the GW170817 binary neutron star merger event. A covariance analysis is performed to estimate the statistical uncertainties of the model parameters as well as correlations among the model parameters and different observables of interest.