Spectroscopy of ${}^{50}$Sc and ab initio calculations of $B(M3)$ strengths

Abstract

The GRIFFIN spectrometer at TRIUMF-ISAC has been used to study excited states and transitions in ${}^{50}$Sc following the $\beta$-decay of ${}^{50}$Ca. Branching ratios were determined from the measured $\gamma$-ray intensities, and angular correlations of $\gamma$ rays have been used to firmly assign the spins of excited states. The presence of an isomeric state that decays by an $M3$ transition with a $B(M3)$ strength of 13.6(7)\,W.u. has been confirmed. We compare with the first {\it ab initio} calculations of $B(M3$) strengths in light and medium-mass nuclei from the valence-space in-medium similarity renormalization group approach, using consistently derived effective Hamiltonians and $M3$ operator. The experimental data are well reproduced for isoscalar $M3$ transitions when using bare $g$-factors, but the strength of isovector $M3$ transitions are found to be underestimated by an order of magnitude.

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Cited by in corpus (6)

• Non-Empirical Interactions for the Nuclear Shell Model: An Update
• The GRIFFIN Facility for Decay-Spectroscopy Studies at TRIUMF-ISAC
• Masses of neutron-rich ${}^{52-54}$Sc and ${}^{54,56}$Ti nuclides: The $N=32$ subshell closure in scandium
• Testing ab initio nuclear structure in neutron-rich nuclei: lifetime measurements of second 2+ states in 16C and 20O
• High-resolution (p,t) reaction measurements as spectroscopic tests of {\it ab-initio} theory in the mid $pf$-shell
• Decay spectroscopy of ${}^{50}$Sc and ${}^{50m}$Sc to ${}^{50}$Ti