Multiple-cell cavity design for high mass axion searches: An extended study

The invisible axion is a well-motivated hypothetical particle which could address two fundamental questions in modern physics—the CP symmetry problem in the strong interactions and the dark matter mystery of our universe. The plausible mass (frequency) range of the QCD axion as a dark matter candidate spans from μeV to meV (O(GHz) to O(THz)). The axion haloscope using a resonant cavity has provided the most sensitive search method in the microwave region. However, experimental searches have been limited to relatively low mass regions mainly due to the reduced cavity volume at high masses. As an effective approach for high-mass axion searches, a unique cavity design, featured by multiple identical cells divided by equidistant thin metal partitions in a single cylindrical cavity, was proposed and successfully demonstrated. We perform an extended study to characterize the multiple-cell cavity design and discuss the various advantages it offers for high-mass axion searches.