1. Constraints on the Decay of Ta180m
- Author
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Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Goett, J, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kim, I, Kouzes, RT, V., TE Lannen, Li, A, López-Castaño, JM, Massarczyk, R, Meijer, SJ, Meijer, W, Oli, TK, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Rouyer, A, Ruof, NW, Schaper, DC, Schleich, SJ, Smith-Gandy, TA, Tedeschi, D, Thompson, JD, Varner, RL, Vasilyev, S, Watkins, SL, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, Alves, DSM, Hebenstiel, L, and Ramani, H
- Subjects
Nuclear and Plasma Physics ,Particle and High Energy Physics ,Synchrotrons and Accelerators ,Physical Sciences ,Affordable and Clean Energy ,Majorana Collaboration ,Mathematical Sciences ,Engineering ,General Physics ,Mathematical sciences ,Physical sciences - Abstract
^{180m}Ta is a rare nuclear isomer whose decay has never been observed. Its remarkably long lifetime surpasses the half-lives of all other known β and electron capture decays due to the large K-spin differences and small energy differences between the isomeric and lower-energy states. Detecting its decay presents a significant experimental challenge but could shed light on neutrino-induced nucleosynthesis mechanisms, the nature of dark matter, and K-spin violation. For this study, we repurposed the Majorana Demonstrator, an experimental search for the neutrinoless double-beta decay of ^{76}Ge using an array of high-purity germanium detectors, to search for the decay of ^{180m}Ta. More than 17 kg, the largest amount of tantalum metal ever used for such a search, was installed within the ultralow-background detector array. In this Letter, we present results from the first year of Ta data taking and provide an updated limit for the ^{180m}Ta half-life on the different decay channels. With new limits up to 1.5×10^{19} yr, we improved existing limits by 1-2 orders of magnitude which are the most sensitive searches for a single β and electron capture decay ever achieved. Over all channels, the decay can be excluded for T_{1/2}
- Published
- 2023