Speaker
Description
The ${\rm M{\small AJORANA}~D{\small EMONSTRATOR}}$ is searching for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{76}$Ge, a beyond the standard model process that would prove the neutrino is a Majorana fermion if discovered.
The experiment has completed operation of a modular array of 44 kg of high purity germanium detectors, in the p-type point contact (PPC), inverted-coaxial point-contact (ICPC), and broad energy germanium (BEGe) detector geometries.
${\rm M{\small AJORANA}}$ operated up to 30 kg of PPC detectors and 7 kg of ICPC detectors at a time, which were enriched to 88% in $^{76}$Ge.
To minimize backgrounds, the ${\rm D{\small EMONSTRATOR}}$ is constructed from low-background materials and housed inside a compact shield consisting of lead and copper at the Sanford Underground Research Facility (SURF) in Lead, SD.
The experiment has achieved a world leading energy resolution of 0.12% FWHM at 2039 keV.
Since the previous data release in 2019, ${\rm M{\small AJORANA}}$ has upgraded the electronic cables and connectors, improved its analysis routines, and successfully operated the ICPC detectors.
In March 2021, operation of the enriched detectors ended so that they could be deployed in the LEGEND-200 experiment, and the experiment continues to run with a single module with natural abundance BEGe detectors for background studies and other physics searches.
This talk will present results from the ${\rm M{\small AJORANA}~D{\small EMONSTRATOR}}$ with its full exposure of 65 kg-yr from enriched detectors, and future plans for the experiment.
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.
