Beta decay of the exotic $T_z$ = -2 nuclei $^{48}$Fe, $^{52}$Ni and $^{56}$Zn

TL;DR

This study investigates the beta decay properties of three proton-rich $T_z=-2$ nuclei, providing detailed decay schemes, energy levels, and transition strengths, and revealing competition between decay modes and exotic decay pathways.

Contribution

The paper presents new experimental data on the decay schemes, energy levels, and transition strengths of $^{48}$Fe, $^{52}$Ni, and $^{56}$Zn, including the first observation of exotic $eta$-delayed $ ext{γ}$-proton decay in $^{56}$Zn.

Findings

Decay schemes and new energy levels identified for all three nuclei.

Competition observed between $eta$-delayed protons and $ ext{γ}$ rays.

Exotic $eta$-delayed $ ext{γ}$-proton decay observed in $^{56}$Zn.

Abstract

The results of a study of the beta decays of three proton-rich nuclei with $T_z=\text{-}2$, namely $^{48}$Fe, $^{52}$Ni and $^{56}$Zn, produced in an experiment carried out at GANIL, are reported. In all three cases we have extracted the half-lives and the total $\beta$-delayed proton emission branching ratios. We have measured the individual $\beta$-delayed protons and $\beta$-delayed $\gamma$ rays and the branching ratios of the corresponding levels. Decay schemes have been determined for the three nuclei, and new energy levels are identified in the daughter nuclei. Competition between $\beta$-delayed protons and $\gamma$ rays is observed in the de-excitation of the $T=2$ Isobaric Analogue States in all three cases. Absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. In addition, we discuss in detail the data analysis taking as a test case $^{56}$Zn, where the exotic $\beta$-delayed $\gamma$-proton decay has been observed.