Results on ββ decay with emission of two neutrinos or Majorons in 76 Ge from GERDA Phase I
(LNGS, Assergi, Italy); M. Agostini (Physik Department and Excellence Cluster Universe, Technische Universität München, Munich, Germany); M. Allardt (Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany); A.M. Bakalyarov (National Research Centre “Kurchatov Institute”, Moscow, Russia); M. Balata (INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi, Italy); et al - Show all 115 authors
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 23  yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with 76 Ge. A new result for the half-life of the neutrino-accompanied ββ decay of 76 Ge with significantly reduced uncertainties is also given, resulting in T1/22ν=(1.926±0.094)Ã1021  yr.
