Search for neutrinoless double-beta decay of Mo 100 with the NEMO-3 detector

We report the results of a search for the neutrinoless double-beta decay (0 upsilon beta beta) of Mo-100, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7 kg . y, no evidence for the 0 upsilon beta beta signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T-1/2(0 upsilon beta beta) > 1.1 x 10(24) years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the nuclear matrix elements this corresponds to an upper limit on the Majorana effective neutrino mass of < m(upsilon)> < 0.3-0.9 eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0 upsilon beta beta decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2-10] MeV is observed for an exposure of 47 kg . y.