Isospin mixing in 64,66Ga reexamined via total absorption spectroscopy

Abstract

New measurements of the β decay of 64Ga and 66Ga have been carried out using total absorption spectroscopy at CERN-ISOLDE. The purpose of the study was to determine whether systemic effects such as Pandemonium have affected previous measurements and also determine the degree of isospin mixing in these proton-rich nuclei. Our results show that the β strength distribution of 64Ga was previously underestimated, while that of 66Ga agrees well with previous high-resolution measurements. The results allowed us to determine the amount of isospin mixing in the 0+ → 0+ transitions to the ground states of the daughter nuclei. From the extracted log ft values, we determined the isospin mixing parameter α for the two cases. They were found to be consistent with values for similar transitions in other nuclei. 64Ga exhibits the largest amount of isospin mixing in such nuclei. These findings improve our understanding of beta decay and have implications for nuclear structure models and medical applications of 66Ga in PET imaging.