Survey of excited state neutron spectroscopic factors for Z=8-28 nuclei

TL;DR

This paper systematically analyzes neutron spectroscopic factors in sd and fp shell nuclei, comparing experimental data with shell-model predictions to evaluate the accuracy of current nuclear models across different regions.

Contribution

It provides a comprehensive comparison of 125 experimentally extracted spectroscopic factors with shell-model calculations, highlighting areas of agreement and discrepancy.

Findings

Good agreement for sd-shell nuclei with USDB/USDA interactions.

Significant discrepancies for fp-shell nuclei, especially Ni isotopes.

Current models struggle with core excitation and fragmentation effects.

Abstract

We have extracted 565 neutron spectroscopic factors of sd and fp shell nuclei by systematically analyzing more than 2000 measured (d,p) angular distributions. We are able to compare 125 of the extracted spectroscopic factors to values predicted by large-basis shell-model calculations and evaluate the accuracies of spectroscopic factors predicted by different shell-model interactions in these regions. We find that the spectroscopic factors predicted for most excited states of sd-shell nuclei using the latest USDB or USDA interactions agree with the experimental values. For fp shell nuclei, the inability of the current models to account for the core excitation and fragmentation of the states leads to considerable discrepancies. In particular, the agreement between data and shell-model predictions for Ni isotopes is not better than a factor of two using either the GXPF1A or the XT interaction.