Taiwan axion search experiment with haloscope: Designs and operations

Area of Science:

• Experimental particle physics
• Cosmology
• Astroparticle physics

Background:

• Axions are hypothetical elementary particles proposed as a solution to the strong CP problem in quantum chromodynamics.
• Axions are a compelling dark matter candidate, and their detection is a major goal in physics.
• The Kim-Shifman-Vainshtein-Zakharov (KSVZ) model provides a benchmark for axion properties, including their coupling strength.

Purpose of the Study:

• To search for axions in the mass range around 19.6 µeV using a haloscope.
• To constrain the axion-photon coupling constant (g_aγγ) for axions in this mass range.
• To present the experimental setup and procedures of the Taiwan Axion Search Experiment with Haloscope (TASH).

Main Methods:

• Utilized a frequency-tunable cavity detector with a volume of 0.234 liters.
• Operated the experiment in a strong magnetic field of B₀ = 8 T.
• Employed a signal receiver with a system noise temperature of T_sys ≅ 2.2 K over approximately one month of data collection.

Main Results:

• Excluded axion-photon coupling constants g_aγγ ≳ 8.1 × 10⁻¹⁴ GeV⁻¹ at the 95% confidence level.
• The excluded coupling strength is a factor of 11 above the KSVZ benchmark model.
• The search covered the axion mass range of 19.4687–19.8436 µeV.

Conclusions:

• The TASH experiment has set new limits on axion properties in the µeV mass range.
• The results contribute to the ongoing search for axion dark matter.
• Further improvements in sensitivity and expanded mass range searches are warranted.