Looking into the Nuclear Matrix Elements of Double Beta Decay(Current Topics)

Abstract

Searches of neutrinoless double beta decay are in progress at many laboratories because it is uniquely related to the absolute scale of the neutrino mass. To deduce the mass from the half-life, one needs the nuclear matrix element, which is available only through theoretical calculations of nuclear structure. This article introduces measurements of charge-exchange reactions to examine the present structure calculations on ^<48>Ca, which is a double-beta-decay nucleus decaying to ^<48>Ti. The distributions of the measured Gamow-Teller transition strengths going to the intermediate nucleus ^<48>Sc are not reproduced by the calculations, suggesting that the description of nuclear matrix elements by these calculations is incomplete.