Spin-dependent WIMP scattering off nuclei

Abstract

Chiral effective field theory provides a systematic expansion for the coupling of weakly interacting massive particles (WIMPs) to nucleons at the momentum transfers relevant to direct cold dark matter detection. We derive the currents for spin-dependent WIMP scattering off nuclei at the one-body level and include the leading long-range two-body currents, which are predicted in chiral effective field theory. As an application, we calculate the structure factor for spin-dependent WIMP scattering off $^{129,131}\mathrm{Xe}$ nuclei, using nuclear interactions that have been developed to study nuclear structure and double-beta decays in this region. We provide theoretical error bands due to the nuclear uncertainties of WIMP currents in nuclei.