Analysis strategies for general spin-independent WIMP-nucleus scattering
  We propose a formalism for the analysis of direct-detection dark-matter
searches that covers all coherent responses for scalar and vector interactions
and incorporates QCD constraints imposed by chiral symmetry, including all one-
and two-body WIMP-nucleon interactions up to third order in chiral effective
field theory. One of the free parameters in the WIMP-nucleus cross section
corresponds to standard spin-independent searches, but in general different
combinations of new-physics couplings are probed. We identify the interference
with the isovector counterpart of the standard spin-independent response and
two-body currents as the dominant corrections to the leading spin-independent
structure factor, and discuss the general consequences for the interpretation
of direct-detection experiments, including minimal extensions of the standard
spin-independent analysis. Fits for all structure factors required for the
scattering off xenon targets are provided based on state-of-the-art nuclear
shell-model calculations.
