Surface diffuseness correction in global mass formula

TL;DR

This paper improves a macroscopic-microscopic nuclear mass model by incorporating surface diffuseness corrections, achieving unprecedented accuracy in mass predictions crucial for nuclear physics and astrophysics.

Contribution

It introduces a surface diffuseness correction into the mass formula, reducing rms deviation below 0.3 MeV and refining the symmetry energy coefficient for better nuclear modeling.

Findings

RMS deviation reduced to 298 keV for all mass data

Achieves 258 keV accuracy for neutron separation energies

Attains 237 keV accuracy for alpha-decay Q-values of super-heavy nuclei

Abstract

By taking into account the surface diffuseness correction for unstable nuclei, the accuracy of the macroscopic-microscopic mass formula is further improved. The rms deviation with respect to essentially all the available mass data falls to 298 keV, crossing the 0.3 MeV accuracy threshold for the first time within the mean-field framework. Considering the surface effect of the symmetry potential which plays an important role in the evolution of the "neutron skin" toward the "neutron halo" of nuclei approaching the neutron drip line, we obtain an optimal value of the symmetry energy coefficient J=30.16 MeV. With an accuracy of 258 keV for all the available neutron separation energies and of 237 keV for the alpha-decay Q-values of super-heavy nuclei, the proposed mass formula is particularly important not only for the reliable description of the r-process of nucleosynthesis but also for the study of the synthesis of super-heavy nuclei.