Lawrence Berkeley National Laboratory Recent Work Title Results on ββ decay with emission of two neutrinos or Majorons in 76 Ge from GERDA Phase

A search for neutrinoless ββ decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (Gerda) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices n = 1, 2, 3, 7 were searched for. No signals were found and lower limits of the order of 10 yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with Ge. A new result for the half-life of the neutrino-accompanied ββ decay of Ge with significantly reduced uncertainties is also given, resulting in T 2ν 1/2 = (1.926± 0.095) · 10 21 yr.