Absorption of Axion Dark Matter in a Magnetized Medium

Area of Science:

• * Particle Physics
• * Cosmology
• * Astrophysics

Background:

• * Detecting axion dark matter heavier than 1 meV is challenging due to their small wavelengths limiting traditional experiment volumes.
• * In-medium excitations offer a promising alternative, with energies (meV-eV) independent of detector size.

Purpose of the Study:

• * To demonstrate that electromagnetically coupled axions can be detected via in-medium excitations.
• * To establish that existing dark matter search targets can be repurposed as broadband axion detectors.

Main Methods:

• * Investigating the absorption rate of axions into in-medium excitations within a magnetic field.
• * Analyzing the role of the dielectric function in determining this absorption rate.
• * Simulating detector performance with realistic noise levels and exposure.

Main Results:

• * The absorption rate of axions into in-medium excitations is governed by the target's dielectric function.
• * A kg yr exposure with current noise levels can probe unexplored axion parameter space.
• * Significant noise reduction can enhance sensitivity to QCD axions in the 10 meV–10 eV range.

Conclusions:

• * The proposed method effectively repurposes various materials as broadband axion detectors.
• * This approach opens new avenues for exploring axion dark matter, particularly in the meV-eV mass range.
• * Further noise reduction is crucial for achieving sensitivity to the QCD axion.