Non-collapsing renormalized QRPA with proton-neutron pairing for neutrinoless double beta decay

Using the renormalized quasiparticle random phase approximation (RQRPA), we calculate the light neutrino mass mediated mode of neutrinoless double beta decay (0 nu beta beta-decay) of Ge-76, Mo-100, Te-128 and Te-130. Our results indicate that the simple quasiboson approximation is not good enough to study the 0 nu beta beta-decay, because its solutions collapse for physical values of g(pp). We find that extension of the Hilbert space and inclusion of the Pauli principle in the QRPA with proton-neutron pairing, allows us to extend our calculations beyond the point of collapse, for physical values of the nuclear force strength. As a consequence one might be able to extract more accurate values on the effective neutrino mass by using the best available experimental limits on the half-life of 0 nu beta beta-decay.