Density dependence of the nuclear symmetry energy and neutron skin thickness in the KIDS framework

TL;DR

This study uses the KIDS framework to analyze how variations in nuclear symmetry energy parameters influence neutron skin thickness predictions, highlighting the importance of EoS parameters and nuclear structure details.

Contribution

It presents a systematic exploration of the impact of symmetry energy parameters on neutron skin thickness within the KIDS framework, including effects of structural details.

Findings

Variations in symmetry energy slope parameter L significantly affect NST predictions.

Changes in the curvature parameter $K_\tau$ also impact NST similarly to L.

Structural details notably influence predictions for specific nuclei like $^{68}$Ni and $^{208}$Pb.

Abstract

The KIDS framework for the nuclear equation of state (EoS) and energy density functional (EDF) offers the possibility to explore systematically the effect of EoS parameters on predictions for a variety of observables. The EoS parameters can be varied independently of each other and independently of assumptions regarding the in-medium nucleon effective mass. Here I present a pilot study of the neutron skin thickness (NST) in nuclei of current interest. The results indicate that variations of the symmetry energy slope parameter L by roughly 10 MeV and variations of the droplet-model counterpart of the curvature parameter $K_\tau$ by roughly 20 MeV affect predictions by comparable amounts. However, structural details may also have sizable effects on predictions, notably in the cases of $^{68}$Ni and $^{208}$Pb. This work is part of a systematic investigation of the NST within the KIDS framework and of a broader effort to constrain the density dependence of the nuclear symmetry energy.