Final report on the search for neutrinoless double-βdecay ofGe76from the Gotthard underground experiment

Abstract

BRIEF REPORTS Brief Reports are accounts of completed research which do not warrant regular articles or the priority handling given to Rapid Communications; however, the same standards of scientific quality apply. (Addenda are included in Brief Reports.) A Brief Report may be no longer than fourprintedpages and must be accompanied by an abstract.

The Search for Double Beta Decay With Germanium Detectors: Past, Present, and Future

“…The array was operated for 6.2 kg yr of live time with resulting limits of T 0ν 1/2 ≥2.0(3.4) • 10 23 yr 90%(68%) CL. The final report of this collaboration [40] reported T 0ν 1/2 ≥6.0 • 10 23 yr (68% CL) from 10.0 kg yr. This was the strongest bound from the natural-abundance Ge detectors.…”

False Starts in History of Searches for 2β Decay, or Discoverless Double Beta Decay

“…1992-1994, 2β0ν decay of 130 Te and background peak at 2527 keV. In the data collected with 8 HP Ge detectors at the St. Gotthard Underground Laboratory during 15058 h [24], a small peak at 2527 keV was observed. This has extraordinary importance for calorimetric searches for 2β0ν decay of 130 Te because its Q 2β is also 2527 keV.…”

Neutrinoless Double Beta Decay with Germanium Detectors: 1026 yr and Beyond

“…In the 1970s and 1980s, several research groups started to search for the 0νββ decay of 76 Ge with HPGe detectors, making strong efforts to reduce the background through the use of passive shields, by placing the experiments in underground facilities [40][41][42][43] and by using an active NaI veto [44][45][46][47][48]. The strongest limit on the 0νββ decay half-life reported by a natural Ge experiment was 1.2 × 10 24 yr (UCSB/LBL [48]).…”