Measurement of the half-life of the two-neutrino double beta decay of⁷⁶Ge with the GERDA experiment

Abstract

The primary goal of the GERmanium Detector Array (Gerda) experiment at the\nLaboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless\ndouble beta decay of Ge-76. High-purity germanium detectors made from material\nenriched in Ge-76 are operated directly immersed in liquid argon, allowing for\na substantial reduction of the background with respect to predecessor\nexperiments. The first 5.04 kg yr of data collected in Phase I of the\nexperiment have been analyzed to measure the half-life of the\nneutrino-accompanied double beta decay of Ge-76. The observed spectrum in the\nenergy range between 600 and 1800 keV is dominated by the double beta decay of\nGe-76. The half-life extracted from Gerda data is T(1/2) = (1.84 +0.14 -0.10)\n10^{21} yr.\n