Symmetry Energy as a Function of Density and Mass

TL;DR

This paper investigates how the symmetry energy in nuclear matter varies with density and mass, using experimental data to constrain theoretical models and identify key parameters influencing nuclear properties.

Contribution

It provides new constraints on the density dependence of symmetry energy by analyzing mass-dependent symmetry coefficients derived from excitation energies to isobaric analog states.

Findings

Symmetry coefficient values for intermediate and high masses are well described by specific volume and surface coefficients.

The study estimates the density dependence parameters L~95 MeV and K_{sym}~25 MeV.

Mass dependence of symmetry energy can be constrained by excitation energies to isobaric analog states.

Abstract

Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a_a^V=(31.5-33.5) MeV for the volume coefficient and a_a^S=(9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L~95 MeV and K_{sym}~25 MeV.