The Igex 76ge Neutrinoless Double-Beta Decay Experiment: Prospects for Next Generation Experiments

TL;DR

This paper reports on the IGEX experiment's analysis of germanium detector data, setting new lower bounds on neutrinoless double-beta decay half-life and constraining the Majorana neutrino mass, advancing the search for neutrino properties.

Contribution

It provides updated experimental limits on neutrinoless double-beta decay using pulse-shape discrimination in enriched germanium detectors, informing neutrino mass models.

Findings

Lower bound on decay half-life: >1.57×10^25 years

Upper bound on neutrino mass: 0.33 to 1.35 eV

Analysis of enriched germanium detector data

Abstract

The International Germanium Experiment (IGEX) has analyzed 117 mole yr of 76Ge data from its isotopically enriched (86% 76Ge) germanium detectors. Applying pulse-shape discrimination (PSD) to the more recent data, the lower bound on the half-life for neutrinoless double-beta decay of 76Ge is: $T_{1/2}(0\nu)> 1.57 \times 10^{25}$ yr (90% C.L.). This corresponds to an upper bound in the Majorana neutrino mass parameter,$<m_{\nu}>$, between 0.33 eV and 1.35 eV, depending on the choice of theoretical nuclear matrix elements used in the analysis.