ββ DECAY AND NUCLEAR STRUCTURE

Nuclear matrix elements of ββ decay from β-decay data

The evaluation of the nuclear matrix elements (NME) of the twoneutrino double beta (2νββ) decay and neutrinoless double beta (0νββ) decay using the proton-neutron quasiparticle random-phase approximation (pnQRPA) is addressed. In particular, the extraction of a proper value of the proton-neutron particle-particle interaction parameter, gpp, of this theory is analyzed in detail. Evidence is show...

Disassembling the nuclear matrix elements of the neutrinoless ββ decay

In this article we analyze the nuclear matrix elements (NME) of the neutrinoless double beta decays (0νββ) of the nuclei 48Ca, 76Ge, 82Se, 124Sn, 128Te, 130Te and 136Xe in the framework of the interacting shell model (ISM). We study the relative value of the different contributions to the NME’s, such as higher order terms in the nuclear current, finite nuclear size effects and short range corre...

Limits from Neutrinoless Ββ Decay

Limits on an effective Majorana neutrino mass and a lepton-number violating current admixture can be obtained from lifetime limits on 0νββ nuclear decay. The derived quantities are model-dependent, so the half-life measurements are given first. Where possible we list the references for the matrix elements used in the subsequent analysis. Since rates for the more conventional 2νββ decay serve to...

Neutrino Masses , Mixing and ( Ββ ) 0 Ν − Decay

Nuclear structure and double beta decay

Study of the neutrinoless double beta decay, 0νββ, includes a variety of problems of nuclear structure theory. They are reviewed here. The problems range from the mechanism of the decay, i.e. exchange of the light Majorana neutrino neutrino vesus the exchange of some heavy, so far unobserved particle. Next, the proper expressions for the corresponding operator are described that should include ...