Daily Modulation as a Smoking Gun of Dark Matter with Significant Stopping

Understand

We point out that for a range of parameters, the flux of DM may be stopped significantly by its interactions with the Earth.

• This can significantly degrade the sensitivity of direct detection experiments to DM candidates with large interactions with terrestrial nuclei.
• We find that a significant region of parameter space remains unconstrained for DM $\lesssim $ a few GeV.
• For DM candidates with moderate levels of stopping power, the flux of DM may be blocked from below but not above a detector thereby producing a novel daily modulation.