Correlations between charge radii differences of mirror nuclei and stellar observables

TL;DR

This study explores the link between charge radii differences in mirror nuclei and neutron skin thickness to constrain the nuclear symmetry energy slope parameter L, connecting nuclear physics with neutron star observations.

Contribution

It establishes a correlation between mirror nuclei charge radii differences and neutron skin thickness to set bounds on the symmetry energy slope parameter L.

Findings

Upper limit for L ≈ 100 MeV consistent with NICER constraints.

Lower limit for L ≈ 70 MeV from neutron skin data.

Range L = 70-100 MeV aligns with GW170817 and PREX-2/CREX results.

Abstract

The correlation between the charge radii differences in mirror nuclei pairs and the neutron skin thickness has been studied with the so-called finite range simple effective interaction over a wide mass region. The so far precisely measured charge radii difference data within their experimental uncertainty ranges in the 34Ar-34S, 36Ca-36S, 38Ca-38Ar, and 54Ni-54Fe mirror pairs are used to ascertain an upper limit for the slope parameter of the nuclear symmetry energy L $\approx$ 100 MeV. This limiting value of L is found to be consistent with the upper bound of the NICER PSR J0740+6620 constraint at 1$\sigma$ level for the radius R$_{1.4}$ of 1.4 M$_\odot$ neutron stars. The lower bound of the NICER R$_{1.4}$ data constrains the lower limit of L to $\approx$ 70 MeV. Within the range for L = 70-100 MeV the tidal deformability $\Lambda^{1.4}$ constraint, which is extracted from the GW170817 event at 2$\sigma$ level, and the recent PREX-2 and CREX data on the neutron skin thickness are discussed.