A search for neutrinoless double-β decay (0νββ) in Xe136 is performed with the full EXO-200 dataset using a deep neural network to discriminate between 0νββ and background events. Relative to previous analyses, the signal detection efficiency has been raised from 80.8% to 96.4±3.0%, and the energy resolution of the detector at the Q value of Xe136 0νββ has been improved from σ/E=1.23% to 1.15±0.02% with the upgraded detector. Accounting for the new data, the median 90% confidence level 0νββ half-life sensitivity for this analysis is 5.0×1025 yr with a total Xe136 exposure of 234.1 kg yr. No statistically significant evidence for 0νββ is observed, leading to a lower limit on the 0νββ half-life of 3.5×1025 yr at the 90% confidence level.
|Journal||Physical Review Letters|
|State||Published - Oct 18 2019|
Bibliographical noteFunding Information:
EXO-200 is supported by the DOE and NSF in the U.S., the NSERC in Canada, the SNF in Switzerland, the IBS in Korea, the RFBR (18-02-00550) in Russia, the DFG in Germany, and CAS and ISTCP in China. The EXO-200 data analysis and simulation use resources of the National Energy Research Scientific Computing Center (NERSC). We gratefully acknowledge the KARMEN collaboration for supplying the cosmic-ray veto detectors, as well as the WIPP for their hospitality.
© 2019 authors.
ASJC Scopus subject areas
- Physics and Astronomy (all)