Rice University physicists develop levitating magnet detector to search for ultraheavy dark matter particles
A team led by Christopher Tunnell has created a novel detector using a sand-grain-sized levitating magnet to sense interactions from dark matter particles far heavier than those targeted by traditional experiments.
What happened
Rice University physicists led by Christopher Tunnell levitated a tiny permanent magnet above a superconductor cooled near absolute zero to create a sensitive detector capable of sensing movements as small as one-hundredth of an atom. The detector was designed to register faint impulses—"very small knocks"—that would result if ultraheavy dark matter particles passed through it. Over one month of observations conducted mainly during quiet overnight periods, the team searched across nine orders of magnitude for dark matter particles, including those up to 10 million times heavier than those investigated in prior similar experiments. No definitive detections were made, but the absence of signal allowed the researchers to place constraints on which combinations of dark matter masses and interaction strengths should have produced detectable effects. The research was presented at the 2026 International Conference on Particle Physics and Cosmology.
Context
Dark matter is theorized to comprise most of the matter in the cosmos and influences galaxy formation and behavior, yet remains undetected and its composition unknown. Current dark matter experiments typically target particles with masses similar to atoms or subatomic particles, but some theoretical models propose much heavier candidates—approaching cellular size. The Rice team's detector opens experimental access to a previously unreachable range of dark matter masses that theoretical physicists have studied but lacked experimental tools to test. Future improvements, including cooling the magnet further, extending observation periods, and deploying multiple detectors simultaneously, could increase sensitivity and help distinguish genuine dark matter interactions from false positives caused by vibrations or environmental interference.