Decay spectroscopy of ${}^{50}$Sc and ${}^{50m}$Sc to ${}^{50}$Ti

Abstract

The ${\hat{I}}^2$ decay of the isomeric and ground state of ${}^{50}$Sc to the semi-magic nucleus ${}_{22}^{50}$Ti${}_{28}$ has been studied using a ${}^{50}$Ca beam delivered to the GRIFFIN ${\hat{I}}^3$-ray spectrometer at the TRIUMF-ISAC facility. ${\hat{I}}^2$-decay branching ratios are reported to 16 excited states with a total of 38 ${\hat{I}}^3$-ray transitions linking them. These new data significantly expands the information available over previous studies. Relative intensities are measured to less than 0.001$\%$ that of the strongest transition with the majority of ${\hat{I}}^3$-ray transitions observed here in ${\hat{I}}^2$ decay for the first time. The data are compared to shell-model calculations utilizing both phenomenologically-derived interactions employed in the $pf$ shell as well as a state-of-the-art, $abinitio$ based interaction built in the valence-space in-medium similarity renormalization group framework.

Regular article, nuclear beta decay, gamma-ray spectroscopy, ab initio nuclear model, 12 pages, 5 figures, 3 tables