# Low-energy M1 excitations in $^{208}$Pb and the spin channel of the Skyrme energy-density functional

## TL;DR

This paper examines how the spin-dependent part of the Skyrme energy-density functional affects low-energy M1 excitations in lead-208, proposing modifications to improve excitation predictions while preserving ground state accuracy.

## Contribution

It introduces a method to modify spin-related parameters of the Skyrme functional, enhancing the description of M1 excitations without compromising ground state properties.

## Key findings

- Certain Skyrme parameters strongly influence M1 excitations.
- Modified parameters improve M1 excitation predictions.
- Ground state properties remain well-described after modifications.

## Abstract

We investigate the spin dependent part of the Skyrme energy-density functional, in particular its impact on the residual particle-hole interaction in self-consistent calculations of excitations. Test cases are the low-energy M1 excitations in $^{208}$Pb treated within the self-consistent random-phase approximation based on the Skyrme energy-density functional. We investigate different parametrizations of the functionals to find out which parameters of the functional have strongest correlations with M1 properties. We explore a simple method of the modification of the spin-related parameters which delivers a better description of M1 excitations while basically maintaining the good description of ground state properties.