학술논문
The Majorana Demonstrator's Search for Double-Beta Decay of $^{76}$Ge to Excited States of $^{76}$Se
Document Type
Working Paper
Author
Arnquist, I. J.; Avignone III, F. T.; Barabash, A. S.; Barton, C. J.; Bertrand, F. E.; Blalock, E.; Bos, B.; Busch, M.; Buuck, M.; Caldwell, T. S.; Chan, Y-D.; Christofferson, C. D.; Chu, P. -H.; Clark, M. L.; Cuesta, C.; Detwiler, J. A.; Drobizhev, A.; Edwards, T. R.; Edwins, D. W.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Gilliss, T.; Giovanetti, G. K.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R.; Henning, R.; Aguilar, D. Hervas; Hoppe, E. W.; Hostiuc, A.; Kidd, M. F.; Kim, I.; Kouzes, R. T.; Lopez, A. M.; López-Castaño, J. M.; Martin, E. L.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Myslik, J.; Oli, T. K.; Othman, G.; Paudel, L. S.; Pettus, W.; Poon, A. W. P.; Radford, D. C.; Reine, A. L.; Rielage, K.; Ruof, N. W.; Saykı, B.; Stortini, M. J.; Tedeschi, D.; Varner, R. L.; Vasilyev, S.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yu, C. -H.; Zhu, B. X.
Source
Phys. Rev. C 103, 015501 (2021)
Subject
Language
Abstract
The Majorana Demonstrator is a neutrinoless double-beta decay search consisting of a low-background modular array of high-purity germanium detectors, $\sim2/3$ of which are enriched to 88\% in $^{76}$Ge. The experiment is also searching for double-beta decay of $^{76}$Ge to excited states (e.s.) in $^{76}$Se. $^{76}$Ge can decay into three daughter states of $^{76}$Se, with clear event signatures consisting of a $\beta\beta$-decay followed by the prompt emission of one or two $\gamma$-rays. This results with high probability in multi-detector coincidences. The granularity of the Demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9~kg-y of isotopic exposure, the Demonstrator has set world leading limits for each e.s.\ decay of $^{76}$Ge, with 90\% CL lower half-life limits in the range of $(0.75-4.0)\times10^{24}$~y. In particular, for the $2\nu$ transition to the first $0^+$ e.s.\ of $^{76}$Se, a lower half-life limit of $7.5\times10^{23}$~y at 90\% CL was achieved.
Comment: 16 pages, 11 figures
Comment: 16 pages, 11 figures