  Direct searches for WIMPs are sensitive to physics well below the weak scale.
In the absence of light mediators, it is fruitful to apply an Effective Field
Theory (EFT) approach accounting only for dark matter (DM) interactions with
Standard Model (SM) fields. We consider a singlet fermion WIMP and effective
operators up to dimension 6 which are generated at the mass scale of particles
mediating DM interactions with the SM. We perform a one-loop Renormalization
Group Evolution (RGE) analysis, evolving these effective operators from the
mediators mass scale to the nuclear scales probed by direct searches. We apply
our results to models with DM velocity-suppressed interactions, DM couplings
only to heavy quarks, leptophilic DM and Higgs portal, which without our
analysis would not get constrained from direct detection bounds. Remarkably, a
large parameter space region for these models is found to be excluded as a
consequence of spin-independent couplings induced by SM loops. In addition to
these examples, we stress that more general renormalizable models for singlet
fermion WIMP can be matched onto our EFT framework, and the subsequent
model-independent RGE can be used to compute direct detection rates. Our
results allow us to properly connect the different energy scales involved in
constraining WIMP models, and to combine information from direct detection with
other complementary searches, such as collider and indirect detection.
