A new experimental limit on lepton non-conservation in double beta decay

A new experiment on neutrinoless double beta decay of 76Ge to the ground and first excited state of 76Se has been carried out in the Mont Blanc Laboratory at a depth of 5000 m.w.e. of rock. Lower limits of 2 x 1022 and (0.8 x 1022 yr have been set for the (0+ - 0+) and 0+ - 2+) transitions, respectively. The corresponding limits on the existence of massive neutrinos and of right handed currents are discussed. (orig.)