Measurement of the Double Beta Decay Half-life of 150-Nd and Search for Neutrinoless Decay Modes with the NEMO-3 Detector

Abstract

The half-life for double beta decay of 150-Nd has been measured by the NEMO-3 experiment at the Modane Underground Laboratory. Using 924.7 days of data recorded with 36.55 g of 150-Nd the half-life for 2nubb decay is measured to be T_1/2^2nu = (9.11+0.25_-0.22}(stat.) +- 0.63 (syst.)) x 10^18 years. The observed limit on the half-life for neutrinoless double beta decay is found to be T_1/2^{0nu} > 1.8 x 10^22 years at 90 % Confidence Level. This translates into a limit on the effective Majorana neutrino mass of <m_{neutrino}><4.0-6.3 eV if the nuclear deformation is taken into account. We also set limits on models involving Majoron emission, right-handed currents and transitions to excited states.