Search for MeV electron recoils from dark matter in EXO-200

We present a search for electron-recoil signatures from the charged-current absorption of fermionic dark matter using EXO-200 detector. report an average electron recoil background rate $6.8 \times 10^{-4}\, \mathrm{cts}\,\mathrm{kg}^{-1}\mathrm{yr}^{-1}\mathrm{keV}^{-1}$ above $4\,\mathrm{MeV}$ and find no statistically significant excess over our projection. Using total ${}^{136}\mathrm{Xe}$ exposure $234.1\,\mathrm{kg}\,\mathrm{yr}$ we exclude new parameter space cross-section masses between $m_\chi = 2.6\,\mathrm{MeV} - 11.6\,\mathrm{MeV}$ with minimum $6\times 10^{-51}\,\mathrm{cm}^2$ at $8.3\,\mathrm{MeV}$ $90\%$ confidence level.