An Estimation of the Rates of (Two-Neutrino) Double Beta Decay and Related Processes

Abstract

The (two-neutrino) double beta decay, the electron capture with positron emission and the double electron capture decay rates are estimated for several nuclides by assuming the dominance of the lowest 1+ state of the intermediate isobar. By using single-β decay matrix elements and energy denominators as experimental imputs we get values independently of nuclear physics calculations. The results for double β- decay are in agreement with the recent geochemical values. Other predictions are within the present experimental sensitivity

Nuclear matrix elements for double-βdecay

“…The separation of PSFs and nuclear matrix elements can be done in two cases: (1) the closure approximation (CA) and (2) the single-state dominance (SSD) approximation [82][83][84][85][86]. In both cases, the inverse half-life can be written as…”

Realistic shell-model calculations of the 2νββ nuclear matrix elements and the role of the shell structure in intermediate states

“…This can also be explained by a similar argument for the nuclei with Z or N = 40 − 50, in which the isolation of the 0g 9/2 orbit plays an essential role. The 128 Te and 130 Te cases [19,20] are a different matter. Another effect such as quadrupole deformation might be necessary to understand this case.…”

The single state dominance hypothesis and the two-neutrino double beta decay of100Mo

“…In Ref. [6] it was suggested that 2νββ-decay transitions, where the first 1 We note that the dominance of the ground state of intermediate nucleus in particular case of 2νββ-decay of 100 Mo was pointed out by A. Griffiths and P. Vogel, who analysed this decay in details [7].…”

“…The SSD hypothesis has been studied both experimentally [6,[10][11][12] and theoretically [7][8][9]. The required beta transition amplitudes to the 1 + 1 state have been deduced from the measured logf t values, i.e., in the model independent way, or have been calculated e.g.…”