Future Directions in the Microwave Cavity Search for Dark Matter Axions

Understand

The axion is a light pseudoscalar particle which suppresses CP-violating effects in strong interactions and also happens to be an excellent dark matter candidate.

• Axions constituting the dark matter halo of our galaxy may be detected by their resonant conversion to photons in a microwave cavity permeated by a magnetic field.
• The current generation of the microwave cavity experiment has demonstrated sensitivity to plausible axion models, and upgrades in progress should achieve the sensitivity required for a definitive search, at least for low mass axions.
• However, a comprehensive strategy for scanning the entire mass range, from 1-1000 $\mu$eV, will require significant technological advances to maintain the needed sensitivity at higher frequencies.