Constraining neutron star properties through parity-violating electron scattering experiments and relativistic point coupling interactions

TL;DR

This paper links parity-violating electron scattering data from calcium and lead to neutron star properties, constraining the nuclear symmetry energy and radii through relativistic energy density functionals, highlighting the need for more precise measurements.

Contribution

It introduces a framework connecting finite nuclei properties from experiments to neutron star characteristics using relativistic point coupling models.

Findings

CREX and PREX-2 data constrain symmetry energy parameters.

Larger neutron star radii are predicted when including fourth-order symmetry energy terms.

Discrepancies exist between constraints from different experiments, indicating need for higher precision data.

Abstract

Parity-violating electron scattering experiments on $\rm ^{48}Ca$ (CREX) and $\rm ^{208}Pb$ (PREX-2) offer valuable insight into the isovector properties of finite nuclei, providing constraints for the density dependence of the nuclear equation of state, which is crucial for understanding astrophysical phenomena. In this work, we establish functional dependencies between the properties of finite nuclei-such as weak charge form factors and neutron skin thickness-and the bulk properties of neutron stars, including tidal deformability from binary neutron star mergers and neutron star radii. The dependencies are formulated by introducing a family of $\beta$-equilibrated equations of state based on relativistic energy density functionals with point coupling interactions. The charge minus the weak form factors derived from CREX and PREX-2 measurements, combined with the observational constraints on tidal deformability from the GW170817 event, are used to constrain the symmetry energy and neutron star radii. Notably, the energy density expanded up to the fourth order in symmetry energy yields larger radii compared to calculations limited to the second order term. However, the results reveal a discrepancy between the constraints provided by the CREX and PREX-2 experiments. For a more quantitative assessment, higher precision parity-violating electron scattering data and neutron star observations are required.