Neutrinoless double beta decay within Self-consistent Renormalized Quasiparticle Random Phase Approximation and inclusion of induced nucleon currents

Abstract

The first, to our knowledge, calculation of neutrinoless double beta decay ($0\hat{I}½{\hat{I}}^2{\hat{I}}^2$-decay) matrix elements within the self-consistent renormalised Quasiparticle Random Phase Approximation (SRQRPA) is presented. The contribution from the momentum-dependent induced nucleon currents to $0\hat{I}½{\hat{I}}^2{\hat{I}}^2$-decay amplitude is taken into account. A detailed nuclear structure study includes the discussion of the sensitivity of the obtained SRQRPA results for $0\hat{I}½{\hat{I}}^2{\hat{I}}^2$-decay of ${}^{76}$Ge to the parameters of nuclear Hamiltonian, two-nucleon short-range correlations and the truncation of the model space. A comparision with the standard and renormalized QRPA is presented. We have found a considerable reduction of the SRQRPA nuclear matrix elements, resulting in less stringent limits for the effective neutrino mass.

13 pages, 3 figures, 1 table