Scientists at Kyoto University and collaborating institutions have utilized Earth’s magnetic field and atmosphere as a large-scale detector in the search for dark matter, specifically ultralight axions and dark photons. The research, conducted using a decade of magnetic data, revealed several intriguing signals requiring further investigation.
Atsushi Taruya, corresponding author of the study, explained the team’s approach: “We asked ourselves whether we could use the Earth itself as a giant detector in the search.” Researchers leveraged the Earth-ionosphere cavity, which naturally resonates with electromagnetic waves, to amplify signals potentially associated with these ultralight particles. This method overcomes limitations of traditional experiments that rely on smaller, laboratory-based magnetic fields.
The team developed a new theoretical framework to expand the search to higher frequencies, overcoming previous limitations that restricted analysis to frequencies below 1 Hz. Their calculations demonstrated that the Earth-ionosphere cavity can amplify signals near 8 Hz, allowing for reliable predictions up to 30 Hz. This model also predicts that axion signals would vary geographically, being strongest in Southeast Asia, while dark photon signals should be consistent globally.
Using a decade of magnetic data, the researchers identified several dark photon signals that remain unexplained. The study dramatically improved limits on ultralight axions as well. Dark matter is estimated to comprise approximately a quarter of the universe’s total energy content, but its composition remains unknown. Ultralight axions and dark photons are two leading hypothetical candidates, being roughly 19 to 21 orders of magnitude lighter than an electron.
Read the original coverage
💬 Comments
📜 Comment Policy