Nuclear Matrix Elements for First-ForbiddenβDecay

Abstract

The first-forbidden $\beta$ decay from the ground states of odd-odd nuclei to the quadrupole vibrational states of even-even nuclei is studied. It is found that the collective motions introduce particle-hole correlations and thereby lead to cancellations, which is the dominant feature of these processes. The region of proton number between 50 and 60 is treated in detail.