# Structure of $^{38}$Cl and the quest for a comprehensive shell model interaction

## TL;DR

This study investigates the high-spin structure of $^{38}$Cl using experimental reactions and extends the level scheme, then develops a new shell model interaction that accurately reproduces observed nuclear properties.

## Contribution

A new multishell interaction was created based on experimental data, improving shell model predictions for $^{38}$Cl and nearby nuclei.

## Key findings

- Extended the level scheme of $^{38}$Cl up to 8420 keV.
- Developed the FSU interaction fitting 270 experimental states.
- Successfully reproduced observed properties and configurations of $^{38}$Cl.

## Abstract

The higher-spin structure of $^{38}$Cl ($N = 21$) was investigated following the $^{26}$Mg($^{14}$C, $pn$) reaction at 30 and 37 MeV beam energies. The outgoing protons were detected in an $E- \Delta E$ Si telescope placed at 0$^\circ$ close to the target with a Ta beam stopper between the target and telescope. Multiple $\gamma$ rays were detected in time coincidence with the protons using an enhanced version of the FSU $\gamma$ detection array. The level scheme was extended up to 8420 keV with a likely spin of 10 $\hbar$. A new multishell interaction was developed guided by the experimental information. This FSU interaction was built by fitting to the energies of 270 experimental states from $^{13}$C to $^{51}$Ti. Calculations using the FSU interaction reproduce observed properties of $^{38}$Cl rather well, including the spectroscopic factors. The interaction has been successfully used to interpret the $1p1h$ and $2p2h$ configurations in some nearby nuclei as well.