Measurement of the two neutrino double beta decay half- life of Zr-96 and search for associated neutrinoless processes with the NEMO-3 detector
/ Authors
J. Argyriades, R. Arnold, C. Augier, J. Baker, A. Barabash, A. Basharina-Freshville, M. Bongrand, G. Broudin-Bay, V. Brudanin, A. Caffrey
and 58 more authors
A. Chapon, E. Chauveau, Z. Daraktchieva, D. Durand, V. Egorov, N. Fatemi-Ghomi, R. Flack, B. Guillon, P. Hubert, S. Jullian, M. Kauer, S. King, A. Klimenko, O. Kochetov, S. Konovalov, V. Kovalenko, D. Lalanne, T. Lamhamdi, K. Lang, Y. Lemière, C. Longuemare, G. Lutter, F. Mamedov, C. Marquet, J. Martín-Albo, F. Mauger, A. Nachab, I. Nasteva, I. Nemchenok, C. Nguyen, F. Nova, P. Novella, H. Ohsumi, R. Pahlka, F. Perrot, F. Piquemal, J. Reyss, J. Ricol, R. Saakyan, X. Sarazin, Y. Shitov, L. Simard, F. Šimkovic, A. Smolnikov, S. Snow, S. Söldner-Rembold, I. Stekl, C. Sutton, G. Szklarz, J. Thomas, V. Timkin, V. Tretyak, V. Umatov, L. Vála, I. Vanyushin, V. Vasiliev, V. Vorobel, T. Vylov
/ Abstract
Using 1221 days of data from the NEMO-3 detector, the measurement of Zr-96 2vbb decay half-life is [2.35 +/- 0.14(stat) +/- 0.19(syst)] x 10^19 yr. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2v nuclear matrix element is extracted using the measured 2vbb half-life and is 0.049 +/- 0.003. A 90% CL limit is set on the 0vbb decay half-life of > 9.2 x 10^21 yr corresponding to a limit on the effective Majorana neutrino mass < 7.2 - 19.5 eV. Limits on other mechanisms of 0vbb decay have also been set.