Forbidden beta decays of ~(96)Zr and ~(115)In: Implications for neutrino physics

摘要

We summarize our theoretical results for two nuclides of interest for the double-beta decay and neutrino mass studies: ~(96)Zr and ~(115) In. The double-beta decay of ~(96)Zr competes with three highly-forbidden beta-decay channels. Our microscopic nuclear-structure calculations [1] imply that the half-life of the first-order beta-decay channels is an order of magnitude longer than that of the double-beta decay. In the work of C. T. Cattadori et al [2] it was discovered that ~(115)In can beta decay to the first excited state of ~(115)Sn. It was also suggested that this decay might provide a supplementary way of accessing the neutrino mass. The recent half-life measurement carried out in the underground laboratory HADES confirms the existence and refines the half-life of this decay channel [3]. At the same time the precision mass measurements made at the University of Jyv?skyl? yield the record- setting ultra-low Q value of 0.35(17) keV [3]. Our theoretical analysis of this decay suggests that atomic effects could play an important role in relating the measured half-life to the measured Q value.