Search for MeV electron recoils from dark matter in EXO-200
S. Al Kharusi, G. Anton, I. Badhrees, P. S. Barbeau, D. Beck, V. Belov, Trilochan Bhatta, M. Breidenbach, T. Brunner, G. F. Cao, W. R. Cen, C. Chambers, B. T. Cleveland, Minor J. Coon, A. Craycraft, T. Daniels, L. Darroch, S. J. Daugherty, J. Davis, S. Delaquis, A. Der Mesrobian-Kabakian, R. DeVoe, J. Dilling, A. Dolgolenko, M. J. Dolinski, J. Echevers, W. M. Fairbank, D. Fairbank, J. Farine, Soheyla Feyzbakhsh, P. Fierlinger, Yanyan Fu, D. Fudenberg, P. Gautam, R. Gornea, G. Gratta, C. Hall, E. V. Hansen, J. Hoessl, P. Hufschmidt, M. Hughes, A. Iverson, A. Jamil, C. E. Jessiman, M. J. Jewell, A. S. Johnson, A. Karelin, L. J. Kaufman, T. Koffas, R. Krücken, A. Kuchenkov, K.S. Kumar, Y. Lan, A. C. Larson, B. G. Lenardo, D. S. Leonard, G. S. Li, S. Li, Z. Li, C. Licciardi, Y. H. Lin, R. MacLellan, Thomas McElroy, Thilo Michel, B. Mong, David C. Moore, K. Murray, O. Njoya, O. Nusair, A. Odian, I. Ostrovskiy, Andréa Perna, A. Piepke, A. Pocar, F. Retière, A. L. Robinson, P.C. Rowson, D. Ruddell, J. Runge, Susann Schmidt, D. Sinclair, K. Skarpaas, A. K. Soma, V. Stekhanov, M. Tarka, S. Thibado, M. Todd, T. Tolba, T.I. Totev, R. Tsang, B. Veenstra, V. Veeraraghavan, P. Vogel, J.-L. Vuilleumier, M. Wagenpfeil, J. Watkins, Liangjian Wen, U. Wichoski, Gerrit Wrede, Sen Wu
Abstract
We present a search for electron-recoil signatures from the charged-current absorption of fermionic dark matter using the EXO-200 detector. We report an average electron-recoil background rate of $6.8\ifmmode\times\else\texttimes\fi{}{10}^{4}\text{ }\text{ }\mathrm{cts}\text{ }{\mathrm{kg}}^{\ensuremath{-}1}\text{ }{\mathrm{yr}}^{\ensuremath{-}1}\text{ }{\mathrm{keV}}^{\ensuremath{-}1}$ above 4 MeV and find no statistically significant excess over our background projection. Using a total $^{136}\mathrm{Xe}$ exposure of 234.1 kg yr, we exclude new parameter space for the charged-current absorption cross section for dark matter masses between ${m}_{\ensuremath{\chi}}=2.6--11.6\text{ }\text{ }\mathrm{MeV}$ with a minimum of $6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}51}\text{ }{\mathrm{cm}}^{2}$ at 8.3 MeV at the 90% confidence level.