Results from the Complete EXO-200 Dataset
ORAL
Abstract
EXO-200 was a low-background time-projection chamber employing a stockpile of 200 kg of xenon enriched to 80.6{\%} in isotope 136 and located underground at the WIPP site outside Carlsbad NM. In its first phase of data-taking between September 2011 and February 2014, the experiment made the first observation of two-neutrino double-beta decay of~136Xe, provided the most precise measurement of any two-neutrino half-life to date, and provided one of the most sensitive searches for neutrinoless double-beta decay. While the first phase ended with the 2014 fire and radiation events at WIPP, a second phase of data collection with upgrades including improved energy resolution extended from May 2016 -- December 2018. Analysis of the complete EXO-200 dataset, representing a total $^{\mathrm{136}}$Xe exposure of 234.1 kg-yr, results in a lower limit of 3.5*10$^{\mathrm{25\thinspace }}$yr on the zero-neutrino double-beta decay half-life, with a median sensitivity of 5.0*10$^{\mathrm{25}}$ yr.
*EXO-200 is supported by DoE and NSF in the United States, NSERC in Canada, SNF in Switzerland, IBS in Korea, RFBR in Russia, DFG in Germany, and CAS and ISTCP in China
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