Hunting for Axions and Hidden Photons in the Wilderness: The Search for Non-Interacting Particles Experimental Hunt (SNIPE Hunt)

The Earth-ionosphere environment can act as a transducer that transforms ultralight bosonic dark matter (axions and hidden photons) into an oscillating magnetic field with a specific pattern across the Earth's surface [1-3]. The Search for Non-interacting Particles Experimental Hunt (SNIPE Hunt) attempts to detect such dark matter-induced magnetic field patterns by making correlated measurements using a network of magnetometers placed in relatively quiet magnetic environments (in remote areas far from human-generated magnetic interference). The first generation of our experiment constrained the parameter space describing hidden-photon and axion dark matter with Compton frequencies in the 0.5–5.0 Hz range [4]. The limits on the kinetic-mixing parameter for hidden-photon dark matter are the most stringent experimental bounds to date in this frequency range. Future generations of the SNIPE Hunt will target higher frequencies (up to 1 kHz range) and will employ induction-coil magnetometers that have orders of magnitude better sensitivity as compared to the sensors used in our original search. In order to clearly interpret the data in terms of dark-matter-induced signals without detailed modeling of complicated features of the Earth's ionosphere, we propose to measure the curl of the magnetic field at each site [5].