Muonium Spectroscopy as a Quantum Sensor for Ultralight Axion Dark Matter

Abstract

High-intensity muon beams could enable a Muonium-based Axion Search through resonant quantum transitions between Hyperfine states (MASH). Combining theoretical calculations with simulation results, we demonstrate that such a muonium-based experimental approach could complement and tighten constraints on the axion-muon coupling beyond existing limits from the muon $g-2$ measurement, over the axion mass range of 18--130 $\mu$eV. These results establish a new spectroscopic channel in muonium that enables searches for axion and axion-like particle dark matter.

Comments: Version to appear in Phys. Rev. Lett