Extracting information on the 0 v ßß decays from the2vß ß decays

OSVALDO CIVITARESE; J. SUHONEN

Nuclear Physics A

Año: 2005 vol. 761 p. 313 - 313

0375-9474

We have analyzed the relation betweenthe two-neutrino ($2\nu\beta\beta$) and neutrinoless ($0\nu\beta\beta$) doublebeta decays of $^{76}$Ge, $^{82}$Se, $^{100}$Mo, and  $^{116}$Cd.The relevant nuclear matrix elements have been calculated by usingthe proton-neutron quasiparticle random-phase approximation (pn-QRPA)with realistic two-body interactions. The dependence of the calculated matrixelements on the strength $g_{\rm pp}$ of the particle-particle part of theproton-neutron two-body interaction is investigated. Recently a procedure wasproposed where data on $2\nu\beta\beta$-decay half-lives could be used to deriveappropriate values of $g_{\rm pp}$ for calculating the $0\nu\beta\beta$-decaymatrix elements. Following this procedure, we have determined theallowed values of $g_{\rm pp}$ by including experimental errors of themeasured $2\nu\beta\beta$-decay half-lives and the uncertainties inthe axial-vector coupling constant $g_{\rm A}$. This set of $g_{\rm pp}$ values isused to predict single-beta and $0\nu\beta\beta$ observables.Careful study of these observables points to serious shortcomings in the adoptedprocedure.