New Constraints on Macroscopic Dark Matter Using Radar Meteor Detectors

TL;DR

This paper proposes using terrestrial radar systems to detect macroscopic dark matter with large masses and cross sections by observing ionization echoes, establishing new constraints on such dark matter candidates.

Contribution

It introduces a novel radar-based detection method for macroscopic dark matter, expanding the search techniques beyond traditional cosmological and astrophysical methods.

Findings

Set new limits on dark matter mass and cross section.

Demonstrated radar detection feasibility for large-mass dark matter.

Provided a complementary approach to existing dark matter constraints.

Abstract

We show that dark-matter candidates with large masses and large nuclear interaction cross sections are detectable with terrestrial radar systems. We develop our results in close comparison to successful radar searches for tiny meteoroids, aggregates of ordinary matter. The path of a meteoroid (or suitable dark-matter particle) through the atmosphere produces ionization deposits that reflect incident radio waves. We calculate the equivalent radar echoing area or `radar cross section' for dark matter. By comparing the expected number of dark-matter-induced echoes with observations, we set new limits in the plane of dark-matter mass and cross section, complementary to pre-existing cosmological limits. Our results are valuable because (A) they open a new detection technique for which the reach can be greatly improved and (B) in case of a detection, the radar technique provides differential sensitivity to the mass and cross section, unlike cosmological probes.