Speaker
Description
The MAJORANA DEMONSTRATOR concluded its search for neutrinoless double-beta decay in 2021. The experiment operated an array of up to 40.4 kg of germanium detectors, 29.7 kg of which were isotopically enriched in $^{76}$Ge. Thanks to its ultra-low backgrounds, excellent energy resolution, and background rejection capabilites, the DEMONSTRATOR was able to execute a broad program of searches for other rare physical processes. One such process is the double-beta decay of $^{76}$Ge into excited states of $^{76}$Se, which has not been observed before. Six possible decay modes exist, each of which produce events spanning multiple detectors that can be separated from backgrounds. The DEMONSTRATOR previously set world-leading limits in the range of $(0.75-4.0)\times10^{24}$ yrs (90\% C.I.) on the various decay modes of $^{76}$Ge. Since then, we have more than doubled the isotopic exposure and implemented improved analysis techniques that enable improved sensitivity. This talk will present an updated search for double-beta decay of $^{76}$Ge to excited states of $^{76}$Se, and will highlight searches for physics beyond the Standard Model that were conducted by the MAJORANA DEMONSTRATOR.
*This material is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, the Particle Astrophysics and Nuclear Physics Programs of the National Science Foundation, and the Sanford Underground Research Facility.
| Submitted on behalf of a Collaboration? | Yes |
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