Axion Dark Matter Search around 6.7  μeV

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• Dark matter constitutes a significant portion of the universe's mass.
• The axion is a compelling dark matter candidate, motivated by solutions to the strong CP problem.
• Haloscopes are experimental devices designed to detect axions by their conversion into photons in a magnetic field.

Purpose of the Study:

• To conduct a sensitive search for axion dark matter within a specific mass range.
• To constrain the axion-photon coupling parameter (g_{aγγ}).
• To probe the theoretically favored QCD axion band.

Main Methods:

• Utilized the CAPP-8TB haloscope, a resonant microwave cavity detector.
• Operated the experiment to search for axion-induced photon signals.
• Analyzed data to set limits on axion properties.

Main Results:

• Achieved unprecedented sensitivity to axion-photon coupling (g_{aγγ}) in the axion mass range of 6.62–6.82 μeV.
• Set the most stringent limits to date for this mass range at a 90% confidence level.
• Explored a portion of the parameter space relevant to QCD axion models.

Conclusions:

• The CAPP-8TB experiment has significantly advanced the search for axion dark matter.
• The results exclude a portion of the parameter space for axion dark matter.
• Future experiments can build upon this sensitivity to further probe axion models.