Symmetry energy at subnuclear densities deduced from nuclear masses

TL;DR

This paper investigates how nuclear masses inform the density dependence of symmetry energy, revealing that lighter, neutron-rich nuclei favor a smaller symmetry energy at subnuclear densities, with implications for nuclear models.

Contribution

It demonstrates a method to connect nuclear mass data with the density dependence of symmetry energy using a macroscopic nuclear model.

Findings

Smaller symmetry energy at subnuclear densities is favored by empirical data.

Lighter, neutron-rich, nondeformed nuclei show this tendency.

Surface symmetry energy properties explain the observed trend.

Abstract

We examine how nuclear masses are related to the density dependence of the symmetry energy. Using a macroscopic nuclear model we calculate nuclear masses in a way dependent on the equation of state of asymmetric nuclear matter. We find by comparison with empirical two-proton separation energies that a smaller symmetry energy at subnuclear densities, corresponding to a larger density symmetry coefficient L, is favored. This tendency, which is clearly seen for nuclei that are neutron-rich, nondeformed, and light, can be understood from the property of the surface symmetry energy in a compressible liquid-drop picture.