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

Abstract

The hypothesis of the single state dominance (SSD) in the calculation of the two-neutrino double beta decay (2νββ-decay) of 100 M o is tested by exact consideration of the energy denominators of the perturbation theory. Both transitions to the ground state as well as to the 0 + and 2 + excited states of the final nucleus 100 Ru are considered. We demonstrate, that by experimental investigation of the single electron energy distribution and the angular correlation of the outgoing electrons, the SSD hypothesis can be confirmed or ruled out by a precise 2νββ-decay measurement (e.g. by NEMO III collaboration). 21.60.Jz; 23.40.Bw; 23.40.Hc PACS number(s):

Nuclear matrix elements for double-βdecay

“…13 that this is approximately the case if we assume SSD in 40 Zr, 42 Mo, 48 Cd, and 60 Nd. This is consistent with previous analyses [85,86]. The smooth behavior can be parametrized as g IBM−2 A,ef f = 1.269A −γ , with γ = 0.18 for IBM-2 (GT).…”

“…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…”

Study of 2β-decay of 100Mo and 82Se using the NEMO3 detector

“…The first one is the higher state dominance (HSD) mechanism and the second is the single state dominance (SSD) mechanism (see ref. [19]). For the SSD mechanism it is assumed that the decay goes via the lowest 1 + state of 100 Tc [20].…”

Double Beta Decay Experiments

“…It should also be noted that the background is as low as about 2.5% of the total number of useful events. By employing the calculated values of the detection efficiencies for 2β(2ν) events, the following half-life values were obtained for 100 Mo and 82 Se: [64,65]. Systematic uncertainties can be decreased using special calibrations and can be improved up to ∼ (3 − 5)%.…”