Search for neutrinoless double- $\beta$ decay in ${}^{76}\mathrm{Ge}$ with 26 kg yr of exposure from the Majorana Demonstrator

Journal Article · Fri Aug 23 00:00:00 EDT 2019 · Physical Review C

DOI:https://doi.org/10.1103/physrevc.100.025501· OSTI ID:1564073

Alvis, S. I.; Arnquist, I. J.; Avignone, F. T.; Barabash, A. S.; Barton, C. J.; Basu, V.; Bertrand, F. E.; Bos, B.; Busch, M.; Buuck, M.; Caldwell, T. S.; Chan, Y-D.; Christofferson, C. D.; Chu, P. -H.; Clark, M.; Cuesta, C.; Detwiler, J. A.; 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.; Hegedus, R. J.; Hehn, L.; Henning, R.; Hervas Aguilar, D.; Hoppe, E. W.; Howe, M. A.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Lopez, A. M.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Myslik, J.; Othman, G.; Pettus, W.; Piliounis, A.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Rielage, K.; Ruof, N. W.; Shanks, B.; Shirchenko, M.; Tedeschi, D.; Varner, R. L.; Vasilyev, S.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C. -H.; Yumatov, V.; Zhitnikov, I.; Zhu, B. X.

The MAJORANA Collaboration is operating an array of high purity Ge detectors to search for the neutrinoless double-beta decay of $$^{76}$$Ge. The MAJORANA DEMONSTRATOR consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in $$^{76}$$Ge) split between two modules constructed from ultra-clean materials. Both modules are contained in a low-background shield at the Sanford Underground Research Facility in Lead, South Dakota. We present updated results on the search for neutrinoless double-beta decay in $$^{76}$$Ge with $$26.0\pm0.5$$ kg-yr of enriched exposure. With the DEMONSTRATOR's unprecedented energy resolution of 2.53 keV FWHM at $$Q_{\beta\beta}$$, we observe one event in the region of interest with 0.65 events expected from the estimated background, resulting in a lower limit on the $$^{76}$$Ge neutrinoless double-beta decay half-life of $$2.7\times10^{25}$$ yr (90% CL) with a median sensitivity of $$4.8\times10^{25}$$ yr (90% CL). Depending on the matrix elements used, a 90% CL upper limit on the effective Majorana neutrino mass in the range of 200-433 meV is obtained. The measured background in the low-background configurations is $$11.9\pm2.0$$ counts/(FWHM t yr).

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of North Carolina, Chapel Hill, NC (United States); Univ. of Tennessee, Knoxville, TN (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Contributing Organization: Majorana Collaboration; Marjorana Collaboration
• Grant/Contract Number: AC02-05CH11231; AC05-00OR22725; AC05-76RL0130; AC52-06NA25396; FG02-97ER41020; FG02-97ER41033; FG02-97ER41041; SC0010254; SC0012612; SC0014445; SC0018060; 89233218CNA000001
• OSTI ID: 1564073
• Alternate ID(s): OSTI ID: 1558732; OSTI ID: 1600645; OSTI ID: 1658866; OSTI ID: 1658939; OSTI ID: 1770102
• Report Number(s): LA-UR-19-20700; PRVCAN; ark:/13030/qt6h9257r5; TRN: US2000844
• Journal Information: Physical Review C, Vol. 100, Issue 2; ISSN 2469-9985
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Double beta decay
Neutrinoless double beta decay
Nuclear structure & decays
59 ≤ A ≤ 89
Baryon & lepton number symmetries
Spectrometers & spectroscopic techniques