Measurement of the half-life of the two-neutrino double beta decay of Ge-76 with the Gerda experiment

TL;DR

The Gerda experiment measured the half-life of the two-neutrino double beta decay of Ge-76 to be approximately 1.84 x 10^{21} years, using enriched germanium detectors immersed in liquid argon to reduce background noise.

Contribution

This study provides a precise measurement of the two-neutrino double beta decay half-life of Ge-76, improving understanding of this rare nuclear process.

Findings

Half-life of Ge-76 two-neutrino double beta decay is (1.84 +0.14 -0.10) x 10^{21} years.

Background reduction techniques in Gerda enable clear detection of decay spectrum.

Data from 5.04 kg yr exposure confirms decay spectrum dominated by Ge-76 decay.

Abstract

The primary goal of the GERmanium Detector Array (Gerda) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of Ge-76. High-purity germanium detectors made from material enriched in Ge-76 are operated directly immersed in liquid argon, allowing for a substantial reduction of the background with respect to predecessor experiments. The first 5.04 kg yr of data collected in Phase I of the experiment have been analyzed to measure the half-life of the neutrino-accompanied double beta decay of Ge-76. The observed spectrum in the energy range between 600 and 1800 keV is dominated by the double beta decay of Ge-76. The half-life extracted from Gerda data is T(1/2) = (1.84 +0.14 -0.10) 10^{21} yr.