Estimation of bounds for left-right mixing from nuclear double beta decay processes

Abstract

Nuclear matrix elements, extracted from a systematic calculation of neutrinoless double beta decay rates for 0 + g.s→o + g.s transitions in 76Ge, 82Se, 128Te, 130Te and 136Xe, have been used to compute bounds on the left-right mixing angle ζ of the weak currents. The parameters of the nuclear model have been fixed by calculating the corresponding two-neutrino double beta decay half lives. The present analysis favours a mixing of the order of |tanξ| < 10 −3 which is to be compared with those obtained in muon decay (|tan ξ| ⩽ 0.035) and in supernova (|tan ξ| ⩽ 10 −5) analysis. It shows that nuclear structure calculations yield estimates on ξ which complement the existing data.