Results of the MAJORANA DEMONSTRATOR's Search for Neutrinoless Double Beta Decay

Abstract

The MAJORANA DEMONSTRATOR recently concluded its search for neutrinoless double-beta decay. The experiment operated an array of up to 40.4 kg of germanium detectors, 27 kg of which were isotopically enriched in 76Ge and housed inside a compact shield consisting of lead and copper at the Sanford Underground Research Facility (SURF) in Lead, SD. The experiment achieved a world leading energy resolution of 0.12% FWHM at 2039 keV, one of the lowest background rates in the region of the 0vBB Q-value, 15.7 +1.4 -1.3 cnts/(FWHM t y), and set a 0vBB half-life limit of T_1/2 > 8.3x10^25 yrs based on its full active exposure of 65 kg yr, resulting in limits on the effective neutrino mass of mBB < 113-269 meV.