Determine when nuclear shell-model choice affects experimental limits

Determine when and whether choosing a particular nuclear shell model for silicon and germanium WIMP–nucleus scattering calculations changes the resulting experimental limits, accounting for the interplay between nuclear form factors and particle-physics coupling constants.

Background

The paper compares silicon and germanium nuclear form factors and exclusion limits obtained with different shell-model interactions, including USD versus USDB for silicon and GCN2850, JUN45, and jj44b for germanium. The resulting sensitivity changes depend on which non-relativistic effective-field-theory operator is considered and on the relative proton and neutron couplings.

Because different nuclear responses can vary in different directions and by different amounts across shell-model interactions, the authors state that it is difficult to identify generally when a particular nuclear model will materially alter an experimental result. The question therefore remains unresolved in general, beyond the specific coupling scenarios and detector assumptions studied in the paper.

References

Indeed, given form factors from two nuclear shell model interactions, it is entirely possible to `tune' coupling constants that give you the maximal possible difference between the models. Thus, it is difficult to be definitive about when and if the choice of a particular nuclear shell model will impact experimental results.

— Impact of nuclear shell model uncertainties on silicon and germanium WIMP-nucleus limits  (2609.24764 - Zurowski et al., 21 Sep 2026) in Section 4, Experimental limits