The role of the induced currents in the mass mechanism of neutrinoless double-beta decay

The nuclear matrix elements of Majorana neutrino mass mechanism of neutrino less double-beta decay have so far been calculated using only contributions from vector axial-vector part and weak magnetism of the nuclear current, w hile other contributions have been neglected. In the present work we are ex amining the effect of weak magnetism and induced pseudoscalar coupling. We have performed calculations within the proton-neutron renormalized quasipar ticle random phase approximation and we have found that these additional co ntributions of the nucleon current, result in a considerable reduction of t he nuclear matrix elements of all nuclei which we have considered. This red uction of the nuclear matrix element makes the extracted limits of the lept on number violating parameters ([m(nu)]) and ([eta(N)]) less stringent yiel ding the best value for [m(nu)] less than 0.51eV for Ge-76.