Progress Toward A $2νββ$ Measurement For The MAJORNA DEMONSTRATOR

Journal Article · 01 December 2019 · Journal of Physics. Conference Series

DOI: https://doi.org/10.1088/1742-6596/1342/1/012117 · OSTI ID:1601291

Gilliss, T.; Abgrall, N.; Alvis, S. I.; Arnquist, Isaac J.; Avignone, Frank T.; Barabash, Alexander S.; Barton, C. J.; Bertrand, F. E.; Bode, T.; Bradley, A. W.; Brudanin, V.; Busch, Matthew; Buuck, M.; Caldwell, Tom S.; Chan, Yuen-Dat; Christofferson, C. D.; Chu, P-H; Cuesta, C.; Detwiler, Jason A.; Dunagan, C. ; Efremenko, Yuri; Ejiri, H.; Elliott, S. R.; Giovanetti, Grahan K.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R.; Hehn, L.; Henning, Reyco; Hoppe, Eric W. ; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, Richard T. ; Lopez, Andrew M.; Martin, R. D.; Massarczyk, Ralph; Meijer, S. J.; Mertens, S.; Myslik, Jordan W.; O’Shaughnessy, C.; Othman, G.; Pettus, Walter C.; Poon, Alan W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Rielage, Keith; Robertson, R. G. H.; Ruof, N. W.; Shanks, B.; Shirchenko, M.; Suriano, Anne-Marie; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, Kris R.; White, B. R.; Wilkerson, J. F.; Wiseman, Clint; Xu, Wenqin; Yakushev, E.; Yu, Chang-Hong; Yumatov, Vladimir; Zhitnikov, I.; Zhu, B. X.

The MAJORNA DEMONSTRATOR is a ⁷⁶Ge-based neutrinoless double-beta decay (0νββ) experiment. Staged at the 4850 ft level of the Sanford Underground Research Facility, the DEMONSTRATOR operates an array of high-purity p-type point contact Ge detectors deployed within a graded passive shield and an active muon veto system. The present work concerns the two-neutrino double-beta decay mode (2νββ) of ⁷⁶Ge. For Ge detectors, having superior energy resolution (0.1%), this mode poses negligible background to the 0νββ mode, even for a ton-scale experiment. However, the measurement of the 2νββ mode allows for careful systematics checks of active detector mass, enrichment fraction, and pulse shape discrimination cuts related to both the 0νββ and 2νββ decay modes. A precision measurement of the 2νββ shape also allows searches for spectral distortions, possibly indicative of new physics, including 0νββχ. Work is underway to construct a full experimental background model enabling a Bayesian fit to the measured energy spectrum and extraction of a precise 2νββ spectrum and half-life.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation (NSF), Particle Astrophysics and Nuclear Physics Programs; Sanford Underground Research Facility
• Contributing Organization: The MAJORNA Collaboration
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1601291
• Report Number(s): PNNL-SA-130534; TRN: US2103625
• Journal Information: Journal of Physics. Conference Series, Vol. 1342, Issue 2020; Conference: XV.International Conference on Topics in Astroparticle and Underground Physics , Sudbury, ON (Canada), 24–28 Jun 2017; ISSN 1742-6588
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English