Nuclear matter and neutron star properties constrained by CREX results and astrophysical constraints: A covariance study*

Abstract The ground state properties of finite, bulk matter, and neutron stars are investigated using a proposed effective interaction (HPU4) of the relativistic mean field model (RMF) that incorporates self and cross-couplings of σ , ω , and ρ mesons with nucleons. This interaction has been constructed by fitting data on binding energies and charge radii of finite nuclei, neutron skin ( ) of nucleus, and astrophysical observations of the maximum masses of neutron stars. ( ) = 0.146±0.019 fm is achieved with soft symmetry energy ( = 27.91±1.31 MeV) and its corresponding slope ( = 42.85±14.26 MeV) at saturation density. An equation of state (EoS) with a composition of β -equilibrated nucleonic and leptonic matter is computed. The nuclear matter and neutron star properties are also analyzed for this interaction and agree well with the astrophysical observations, such as the NICER and GW170817 events. We also perform a statistical analysis to estimate the theoretical errors in coupling parameters and neutron star observables and to determine the correlation coefficients. We observe that the neutron skins of and are strongly correlated and exhibit a strong dependence on , and the curvature of symmetry energy ( ) as suggested from their correlations. A strong correlation of canonical mass neutron star radius, with ρ -meson-nucleon coupling quantified by the term and mixed interaction terms and is also observed.