An improved limit on the neutrinoless double-electron capture of 36 Ar with GERDA

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • GERDA collaboration - , National Institute for Nuclear Physics (Author)
  • Chair of Nuclear Physics
  • University College London
  • University of Zurich
  • Russian Research Centre Kurchatov Institute
  • RAS - Institute for Nuclear Research
  • Max Planck Institute for Nuclear Physics
  • Moscow Engineering Physics Institute
  • University of Padua
  • Technical University of Munich
  • Joint Institute for Nuclear Research
  • Max Planck Institute for Physics (Werner Heisenberg Institute)
  • University of L'Aquila
  • University of Tübingen
  • Duke University
  • European Commission
  • Moscow Institute of Physics and Technology

Abstract

The GERmanium Detector Array (Gerda) experiment operated enriched high-purity germanium detectors in a liquid argon cryostat, which contains 0.33% of 36 Ar, a candidate isotope for the two-neutrino double-electron capture (2 ν ECEC) and therefore for the neutrinoless double-electron capture (0 ν ECEC). If detected, this process would give evidence of lepton number violation and the Majorana nature of neutrinos. In the radiative 0 ν ECEC of 36 Ar, a monochromatic photon is emitted with an energy of 429.88 keV, which may be detected by the Gerda germanium detectors. We searched for the 36 Ar 0 ν ECEC with Gerda data, with a total live time of 4.34 year (3.08 year accumulated during Gerda Phase II and 1.26 year during Gerda Phase I). No signal was found and a 90% CL lower limit on the half-life of this process was established T1 / 2> 1.5 · 10 22 year.

Details

Original languageEnglish
Article number34
JournalEuropean Physical Journal C
Volume84
Issue number1
Publication statusPublished - Jan 2024
Peer-reviewedYes