The optimized point-coupling interaction for the relativistic energy density functional of Hartree-Bogoliubov approach quantifying the nuclear bulk properties

TL;DR

This paper introduces PC-L3R, a new optimized relativistic point-coupling interaction for the Hartree-Bogoliubov model, which improves the accuracy of nuclear bulk property predictions including binding energies and charge radii.

Contribution

The paper develops and validates a new parameter set, PC-L3R, optimized for better reproduction of nuclear observables within the relativistic Hartree-Bogoliubov framework.

Findings

PC-L3R achieves the lowest RMS deviation in binding energy predictions.

Charge radii predictions align well with experimental data.

The model accurately reproduces odd-even staggering of separation energies.

Abstract

We propose a newly optimized nonlinear point-coupling parameterized interaction, PC-L3R, for the relativistic Hartree-Bogoliubov framework with a further optimized separable pairing force by fitting to observables, i.e., the binding energies of 91 spherical nuclei, charge radii of 63 nuclei, and 12 sets of mean pairing gaps consisting of 54 nuclei in total. The separable pairing force strengths of proton and neutron are optimized together with the point-coupling constants, and are justified in satisfactory reproducing the empirical pairing gaps. The comparison of experimental binding energies compiled in AME2020 for 91 nuclei with the ones generated from the present and other commonly used point-coupling interactions indicates that the implementation of PC-L3R in relativistic Hartree-Bogoliubov yields the lowest root-mean-square deviation. The charge radii satisfactory agree with experiment. Meanwhile, PC-L3R is capable of estimating the saturation properties of the symmetric nuclear matter and of appropriately predicting the isospin and mass dependence of binding energy. The experimental odd-even staggering of single nucleon separation energies is well reproduced. The comparison of the estimated binding energies for 7,373 nuclei based on the PC-L3R and other point-coupling interactions is also presented.