Search for tri-nucleon decays of 76 Ge in GERDA

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung


  • University College London
  • University of Zurich
  • Russian Research Centre Kurchatov Institute
  • National Institute for Nuclear Physics
  • RAS - Institute for Nuclear Research
  • Max Planck Institute for Nuclear Physics
  • Moscow Engineering Physics Institute
  • Università degli studi di Padova
  • Technische Universität München
  • Max Planck Institute for Physics (Werner Heisenberg Institute)
  • University of L'Aquila
  • Joint Institute for Nuclear Research
  • Eberhard Karls Universität Tübingen
  • Duke University
  • European Commission
  • Moscow Institute of Physics and Technology
  • Leibniz Institute for Crystal Growth


We search for tri-nucleon decays of 76 Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to 73 Cu, 73 Zn, and 73 Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of 73 Ga to 73 Ge (stable). We search for the 73 Ga decay exploiting the fact that it dominantly populates the 66.7 keV 73m Ga state with half-life of 0.5 s. The nnn-decays of 76 Ge that proceed via 73m Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2 × 10 26 yr (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.


Seiten (von - bis)1-8
FachzeitschriftEuropean Physical Journal C
PublikationsstatusVeröffentlicht - Sept. 2023