Search for the double-beta decay of 82Se to the excited states of 82Kr with NEMO-3

Arnold R.; Augier C.; Barabash A. S.; Basharina-Freshville A.; Blondel S.; Blot S.; Bongrand M.; Boursette D.; Breier R.; Brudanin V.; Busto J.; Caffrey A. J.; Calvez S.; Cascella M.; Cerna C.; Cesar J. P.; Chapon A.; Chauveau E.; Chopra A.; Dawson L.; Duchesneau D.; Durand D.; Egorov V.; Eurin G.; Evans J. J.; Fajt L.; Filosofov D.; Flack R.; Garrido X.; Girard-Carillo C.; Gomez H.; Guillon B.; Guzowski P.; Hodak R.; Huber A.; Hubert P.; Hugon C.; Jullian S.; Klimenko A.; Kochetov O.; Konovalov S. I.; Kovalenko V.; Lalanne D.; Lang K.; Lemiere Y.; Le Noblet T.; Liptak Z.; Liu X. R.; Loaiza P.; Lutter G.; Macko M.; Macolino C.; Mamedov F.; Marquet C.; Mauger F.; Minotti A.; Morgan B.; Mott J.; Nemchenok I.; Nomachi M.; Nova F.; Nowacki F.; Ohsumi H.; Oliviero G.; Pahlka R. B.; Palusova V.; Patrick C.; Perrot F.; Pin A.; Piquemal F.; Povinec P.; Pridal P.; Ramachers Y. A.; Remoto A.; Reyss J. L.; Richards B.; Riddle C. L.; Rukhadze E.; Saakyan R.; Salazar R.; Sarazin X.; Sedgbeer J.; Shitov Y.; Simard L.; Simkovic F.; Smetana A.; Smolek K.; Smolnikov A.; Soldner-Rembold S.; Soule B.; Stekl I.; Suhonen J.; Sutton C. S.; Szklarz G.; Tedjditi H.; Thomas J.; Timkin V.; Torre S.; Tretyak V. I.; Tretyak V. I.; Umatov V. I.; Vanushin I.; Vilela C.; Vorobel V.; Waters D.; Xie F.; Zukauskas A.

doi:10.1016/j.nuclphysa.2020.121701

The double-beta decay of 82Se to the 01+ excited state of 82Kr has been studied with the NEMO-3 detector using 0.93 kg of enriched 82Se measured for 4.75 y, corresponding to an exposure of 4.42 kg⋅y. A dedicated analysis to reconstruct the γ-rays has been performed to search for events in the 2e2γ channel. No evidence of a 2νββ decay to the 01+ state has been observed and a limit of T1/22ν(Se82,0gs+→01+)>1.3×1021y at 90% CL has been set. Concerning the 0νββ decay to the 01+ state, a limit for this decay has been obtained with T1/20ν(Se82,0gs+→01+)>2.3×1022y at 90% CL, independently from the 2νββ decay process. These results are obtained for the first time with a tracko-calo detector, reconstructing every particle in the final state.