Search for Two-Neutrino Double Electron Capture of ${}^{124}$Xe with XENON100

Abstract

Two-neutrino double electron capture is a rare nuclear decay where two electrons are simultaneously captured from the atomic shell. For ${}^{124}$Xe this process has not yet been observed and its detection would provide a new reference for nuclear matrix element calculations. We have conducted a search for two-neutrino double electron capture from the K-shell of ${}^{124}$Xe using 7636 kg$\cdot$d of data from the XENON100 dark matter detector. Using a Bayesian analysis we observed no significant excess above background, leading to a lower 90 % credibility limit on the half-life $T_{1/2}>6.5\times 10^{20}$ yr. We also evaluated the sensitivity of the XENON1T experiment, which is currently being commissioned, and find a sensitivity of $T_{1/2}>6.1\times 10^{22}$ yr after an exposure of 2 t$\cdot$yr.

6 pages, 4 figures

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• Dark Matter Results from 225 Live Days of XENON100 Data
• DARWIN: towards the ultimate dark matter detector
• Observation of Anti-correlation between Scintillation and Ionization for MeV Gamma-Rays in Liquid Xenon
• Nuclear deformation and the two neutrino double-βdecay in ^{124,126}Xe,^{128,130}Te, ^{130,132}Ba and ^{150}Nd isotopes
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Cited by in corpus (7)

• First observation of two-neutrino double electron capture in ${}^{124}$Xe with XENON1T
• Neutrinoless Double-Electron Capture
• Double-Weak Decays of ${}^{124}$Xe and ${}^{136}$Xe in the XENON1T and XENONnT Experiments
• Two-neutrino double electron capture of ${}^{124}$Xe in the first LUX-ZEPLIN exposure
• Search for two neutrino double electron capture of ${}^{124}$Xe and ${}^{126}$Xe in the full exposure of the LUX detector
• Large-scale shell-model study of 2$\nu$ECEC process in ${}^{78}$Kr
• Large-scale shell-model investigation of $2\nu$ECEC in ${}^{132}$Ba and ${}^{78}$Kr