Search for inelastic scattering of WIMP dark matter in XENON1T

Abstract

We report the results of a search for the inelastic scattering of weakly interacting massive particles (WIMPs) in the XENON1T dark matter experiment. Scattering off $^{129}\mathrm{Xe}$ is the most sensitive probe of inelastic WIMP interactions, with a signature of a 39.6 keV deexcitation photon detected simultaneously with the nuclear recoil. Using an exposure of 0.83 tonne-years, we find no evidence of inelastic WIMP scattering with a significance of more than $2\ensuremath{\sigma}$. A profile-likelihood ratio analysis is used to set upper limits on the cross section of WIMP-nucleus interactions. We exclude new parameter space for WIMPs heavier than $100\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$, with the strongest upper limit of $3.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}39}\text{ }\text{ }{\mathrm{cm}}^{2}$ for $130\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$ WIMPs at 90% confidence level.