Study of 2β-decay of 100Mo and 82Se using the NEMO3 detector

Abstract

After analysis of 5797 h of data from the detector NEMO3, new limits on neutrinoless double beta decay of 100Mo (T 1/2>3.1×1023y, 90% CL) and 82Se (T 1/2>1.4×1023y, 90% CL) have been obtained. The corresponding limits on the effective majorana neutrino mass are: 〈m v〉<(0.8–1.2) eV and 〈m v〉<(1.5–3.1) eV, respectively. Also the limits on double-beta decay with Majoron emission are: T 1/2>1.4×1022y (90% CL) for 100Mo and T 1/2>1.2×1022y (90% CL) for 82Se. Corresponding bounds on the Majoron-neutrino coupling constant are 〈 g ee〉<(0.5–0.9)×10−4 and <(0.7−1.6)×10−4. Two-neutrino 2β-decay half-lives have been measured with a high accuracy, $$T_{1/2}^{100_{Mo} } = [7.68 \pm 0.02(stat) \pm 0.54(syst)] \times 10^{18} y$$ and $$T_{1/2}^{82_{Se} } = [10.3 \pm 0.3(stat) \pm 0.7(syst)] \times 10^{19} y$$ .