How blind are underground and surface detectors to strongly interacting Dark Matter?

TL;DR

This paper uses Monte Carlo simulations to accurately determine the cross section at which underground and surface dark matter detectors become insensitive due to Earth's shielding, revealing a parameter space region they cannot probe.

Contribution

It provides a more precise calculation of the critical dark matter-nucleus cross section, highlighting a blind spot in current detection capabilities that was previously overestimated.

Findings

Identifies a parameter space where detectors are blind to dark matter.

Shows that increasing exposure cannot close this detection gap.

Suggests surface or high-altitude experiments are needed to probe this region.

Abstract

Above a critical dark matter-nucleus scattering cross section any terrestrial direct detection experiment loses sensitivity to dark matter, since the Earth crust, atmosphere, and potential shielding layers start to block off the dark matter particles. This critical cross section is commonly determined by describing the average energy loss of the dark matter particles analytically. However, this treatment overestimates the stopping power of the Earth crust. Therefore the obtained bounds should be considered as conservative. We perform Monte Carlo simulations to determine the precise value of the critical cross section for various direct detection experiments and compare them to other dark matter constraints in the low mass regime. In this region we find parameter space where typical underground and surface detectors are completely blind to dark matter. This "hole" in the parameter space can hardly be closed with an increase in the detector exposure. Dedicated surface or high-altitude experiments may be the only way to directly probe this part of the parameter space.