The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)

Abstract

The observation of neutrinoless double-beta decay (0 nu beta beta) would show that lepton number is violated, reveal that neutrinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of similar to 0.1 count/(FWHM.t.yr) in the region of the signal. The current generation Ge-76 experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0 nu beta beta signal region of all 0 nu beta beta experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale Ge-76 experiment. The collaboration aims to develop a phased 0 nu beta beta experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results