IGEX<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>76</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">Ge</mml:mi></mml:math>neutrinoless double-beta decay experiment: Prospects for next generation experiments

The International Germanium Experiment (IGEX) has analyzed 117 mol yr of ${}^{76}\mathrm{Ge}$ data from its isotopically enriched (86% ${}^{76}\mathrm{Ge})$ germanium detectors. Applying pulse-shape discrimination to the more recent data, the lower bound on the half-life for neutrinoless double-beta decay of ${}^{76}\mathrm{Ge}$ is ${T}_{1/2}(0\ensuremath{\nu})&gt;1.57\ifmmode\times\else\texttimes\fi{}{10}^{25}\mathrm{yr}$ (90% C.L.). This corresponds to an upper bound in the Majorana neutrino mass parameter, $〈{m}_{\ensuremath{\nu}}〉,$ between 0.33 and 1.35 eV, depending on the choice of theoretical nuclear matrix elements used in the analysis.