Variations on a theme by Skyrme

TL;DR

This paper surveys the parameter adjustment of the Skyrme-Hartree-Fock model for nuclear structure, analyzing how different data and nuclear matter properties influence the model's predictive capabilities and uncertainties.

Contribution

It systematically evaluates the impact of various nuclear data and matter properties on Skyrme-Hartree-Fock parameterization and assesses the model's predictive uncertainties.

Findings

Ground-state data allow broad parameter choices.

Giant resonances help constrain model parameters.

Uncertainties vary depending on the observable.

Abstract

We present a survey of the phenomenological adjustment of the parameters of the Skyrme-Hartree-Fock (SHF) model for a self-consistent description of nuclear structure and low-energy excitations. A large sample of reliable input data from nuclear bulk properties (energy, radii, surface thickness) is selected guided by the criterion that ground-state correlations should remain small. Least squares fitting techniques are used to determine the SHF parameters which accommodate best the given input data. The question of the predictive value of the adjustment is scrutinized by performing systematic variations with respect to chosen nuclear matter properties (incompressibility, effective mass, symmetry energy, and sum-rule enhancement factor). We find that the ground-state data, although representing a large sample, leave a broad range of choices, i.e. a broad range of nuclear matter properties. Information from giant resonances is added to pin down more precisely the open features. We then apply the set of newly adjusted parameterizations to several more detailed observables such as neutron skin, isotope shifts, and super-heavy elements. The techniques of least-squares fitting provide safe estimates for the uncertainties of such extrapolations. The systematic variation of forces allows to disentangle the various influences on a given observable and to estimate the predictive value of the SHF model. The results depend very much on the observable under consideration.