2015/10/31 by XMASS Collaboration, K. Abe, K. Hiraide +51 · 18 citations
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Detector #Double beta decay #Electron #Electron capture #Electron neutrino #Lepton #Limit (mathematics) #Neutrino #Neutrino Physics Research #Neutrino detector #Neutrino oscillation #Nuclear physics #Nuclear physics research studies #Optics #Particle physics #Physics #hep-ex #nucl-ex #physics.ins-det
paper · pdf · open access · doi:10.1016/j.physletb.2016.05.039
published in Physics Letters B 759, 64-68 (Elsevier BV) · 6 pages, 3 figures, accepted for publication in Physics Letters B
openalex publication_date 2016/05/18 · arxiv created 2016/05/26 · arxiv updated 2016/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on 124 Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as 4.7 × 10 21 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the 126 Xe two-neutrino double electron capture half-life of 4.3 × 10 21 years at 90% confidence level as well.