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Free keywords:
Nuclear Experiment, nucl-ex, Physics, Instrumentation and Detectors, physics.ins-det
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 $T_{1/2}>6.5\times10^{20}$
yr. We also evaluated the sensitivity of the XENON1T experiment, which is
currently being commissioned, and find a sensitivity of
$T_{1/2}>6.1\times10^{22}$ yr after an exposure of 2 t$\cdot$yr.
