Detailed spectroscopy of $^{46}$Ca: A study of the $\beta^-$ decay of $^{46}$K

TL;DR

This study provides a detailed level scheme of $^{46}$Ca through high-statistics $eta^-$ decay data of $^{46}$K, comparing experimental results with theoretical models to understand nuclear structure and proton behavior.

Contribution

It offers the first comprehensive spectroscopy of $^{46}$Ca from $^{46}$K decay, including spin-parity assignments and mixing ratios, and compares findings with advanced theoretical calculations.

Findings

Identification of 42 excited states in $^{46}$Ca.

Reasonable agreement between experimental data and microscopic valence-space Hamiltonian predictions.

Protons in this region are less inert than expected for semi-magic nuclei.

Abstract

We report on high-statistics data from the $\beta^-$ decay of the $^{46}$K $J^{\pi}$ = 2$^-$ ground state taken with the GRIFFIN spectrometer located at the TRIUMF-ISAC facility. In total, 199 $\gamma$ rays and 42 excited states were placed in the level scheme, and from the observed $\beta$ feeding and angular correlations of pairs of cascading $\gamma$ rays, it was possible to assign spins and parities to excited states and determine mixing ratios for selected $\gamma$ rays. The level structure of $^{46}$Ca is compared to theoretical predictions from a microscopic valence-space Hamiltonian derived from two- (NN) and three-nucleon (3N) forces. These calculations are in reasonable agreement with the experimental data and indicate that the protons in this region are not as inert as would be expected for semi-magic nuclei.