Speaker
Description
We present a novel search for ultralight dark matter using terrestrial magnetic field measurements at frequencies below 100 Hz, focusing on dark photon dark matter as a representative candidate. Coherently oscillating dark photon dark matter can induce a monochromatic magnetic field via kinetic mixing with ordinary photons. Notably, for dark photon masses around 3 \times 10^{-14} eV, the signal can be resonantly amplified within a cavity formed by the Earth's surface and the ionosphere. We compute the expected signal incorporating the effect of atmospheric conductivity, and derive new upper limits on the kinetic mixing parameter from long-term geomagnetic data. These limits improve upon previous ground-based constraints in the mass range of 1 \times 10^{-15} — 2 \times 10^{-13} eV. We would also like to touch on the results of axion dark matter searches based on similar ideas.
| Research Area | Dark Matter: direct detection |
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