Abstrakt
We report the results of a search for the neutrinoless double-β decay (0νββ) of 100Mo, 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 0νββ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of T1=2 ð0νββÞ > 1.1 x 1024 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 hmνi < 0.3-0.9 eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0νββ 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.