Dark matter particles hitting Earth might have left detectable traces in the crystal structure of ancient rocks.

Searches for dark matter particles called weakly interacting massive particles (WIMPs), which look for the nuclear recoil caused by WIMPs hitting a detector, have so far failed to deliver evidence for WIMPs. In the 1990s, researchers had explored an alternative method based on analyzing ancient rocks, which might contain signatures — in the form of nanometer-wide tracks — of past dark matter interactions. Searches for these so-called dark matter fossils have so far come up empty, but a team now suggests that advances in material analysis could lead to a sensitivity surpassing that of conventional search methods. The team estimates that a cubic centimeter of certain minerals from deep drill cores could hold hundreds to thousands of dark-matter-induced tracks, which could be revealed through microscopy and X-ray scattering experiments.

Reference:
Andrzej K. Drukier, Sebastian Baum (The Oskar Klein Centre for Cosmoparticle Physics, Stockholm University, sbaum@fysik.su.se) Katherine Freese, Maciej Gorski, and Patrick Stengel, “Paleo-Detectors: Searching for Dark Matter with Ancient Minerals,” Physical Review D [https://journals.aps.org/prd (expected publication date: Feb 26), preprint: https://arxiv.org/abs/1811.06844].

Authors’ geographical listing: Sweden, U.S., Poland