The Majorana Demonstrator's Search for Double-Beta Decay of ${}^{76}$Ge to Excited States of ${}^{76}$Se

Abstract

The Majorana Demonstrator is a neutrinoless double-beta decay search consisting of a low-background modular array of high-purity germanium detectors, $\sim 2/3$ 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 $(0.75-4.0)\times 10^{24}$~y. In particular, for the $2\nu$ transition to the first $0^{+}$ e.s.\ of ${}^{76}$Se, a lower half-life limit of $7.5\times 10^{23}$~y at 90\% CL was achieved.

arXiv comment16 pages, 11 figures

References in corpus (30)

• Double Beta Decay, Majorana Neutrinos, and Neutrino Mass
• Limits and Confidence Intervals in the Presence of Nuisance Parameters
• Neutrinoless Double-Beta Decay: Status and Prospects
• Status and Future of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay: A Review
• Theory of neutrinoless double beta decay
• Phase space factors for double-$\beta$ decay
• Disassembling the Nuclear Matrix Elements of the Neutrinoless double beta Decay
• Neutrinoless double beta decay: 2015 review
• Final Results of GERDA on the Search for Neutrinoless Double-$\beta$ Decay
• $0\nu \beta \beta$ and $2\nu \beta \beta$ nuclear matrix elements in the interacting boson model with isospin restoration
• Large-Mass Ultra-Low Noise Germanium Detectors: Performance and Applications in Neutrino and Astroparticle Physics
• The event generator DECAY4 for simulation of double beta processes and decay of radioactive nuclei
• The Large Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND)
• Search for Zero-Neutrino Double Beta Decay in 76Ge with the Majorana Demonstrator
• Average and recommended half-life values for two neutrino double beta decay
• \textsc{MaGe} - a {\sc Geant4}-based Monte Carlo Application Framework for Low-background Germanium Experiments
• Probing Majorana neutrinos with double-$\beta$ decay
• Neutrinoless Double Beta Decay
• A Search for Neutrinoless Double-Beta Decay in ${}^{76}$Ge with 26 kg-yr of Exposure from the MAJORANA DEMONSTRATOR
• The Majorana Demonstrator Radioassay Program
• Impact of the quenching of $g_{\mathrm{A}}$ on the sensitivity of $0\nu \beta \beta$ experiments
• Distinguishing the neutrinoless double beta decay mechanisms
• Investigation of $\beta \beta$ decay in ${}^{150}$Nd and ${}^{148}$Nd to the excited states of daughter nuclei
• Statistics of neutrinos and the double beta decay
• Possible violation of the spin-statistics relation for neutrinos: cosmological and astrophysical consequences
• Multi-site event discrimination for the MAJORANA DEMONSTRATOR
• $2\nu \beta \beta$ decay of ${}^{76}$Ge into excited states with GERDA Phase I
• Large Plastic Scintillator Panels with WLS Fiber Readout; Optimization of Components
• Gamow-Teller and double-beta decays of heavy nuclei within an effective theory
• Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of ${}^{76}$Ge to Excited States of ${}^{76}$Se

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• Final Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of ${}^{76}$Ge to Excited States of ${}^{76}$Se
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