In-beam spectroscopic studies of $^{44}$S nucleus

TL;DR

This study used in-beam gamma-ray spectroscopy at GANIL to explore the structure of $^{44}$S, revealing shape coexistence and new gamma transitions, supported by shell model calculations.

Contribution

First detailed level scheme of $^{44}$S up to 3301 keV, confirming shape coexistence and observing new gamma transitions.

Findings

Confirmed spherical 2+_2 state

Observed three new gamma transitions

Supported shape coexistence with shell model

Abstract

The structure of the $^{44}$S nucleus has been studied at GANIL through the one proton knock-out reaction from a $^{45}$Cl secondary beam at 42 A$\cdot$MeV. The $\gamma$ rays following the de-excitation of $^{44}$S were detected in flight using the 70 BaF${_2}$ detectors of the Ch\^{a}teau de Cristal array. An exhaustive $\gamma\gamma$-coincidence analysis allowed an unambiguous construction of the level scheme up to an excitation energy of 3301 keV. The existence of the spherical 2$^+_2$ state is confirmed and three new $\gamma$-ray transitions connecting the prolate deformed 2$^+_1$ level were observed. Comparison of the experimental results to shell model calculations further supports a prolate and spherical shape coexistence with a large mixing of states built on the ground state band in $^{44}$S.