Cosmic Axion Background Detection Using Resonant Cavity Arrays

Abstract

The axion is a well-motivated and generic extension of the Standard Model. If produced in the early universe, axions may still be relativistic today, forming a Cosmic Axion Background (C$a$B) potentially detectable in direct detection experiments. Although C$a$B is expected to be broadband, which makes it challenging to be detected, a high-quality-factor microwave cavity acts as a narrowband filter with response peaked at its resonant frequency. We propose a new strategy using multi-cavity arrays to distinguish signal from background noise by exploiting spatial correlations of the axion-induced electric field which are set by the cavity quality factor. We compute the two-point correlation function for electric fields in spatially separated cavities sourced by an isotropic C$a$B. Analyzing various cavity geometries, we find that stacked, wide-base cavity arrays offer coherent enhancement of the axion signal. We apply our formalism to prospective upgrades of the ADMX experiment, including configurations with four and eighteen coupled cavities. Although these arrays do not achieve a coherent enhancement, optimizing the geometry could potentially yield an $\mathcal{O}(1)$ improvement in the sensitivity to the C$a$B.

20 pages, 5 figures v2: Accepted version for publication in JHEP

References in corpus (25)

• Asymptotic formulae for likelihood-based tests of new physics
• Introduction to Quantum Noise, Measurement and Amplification
• New CAST Limit on the Axion-Photon Interaction
• A SQUID-based microwave cavity search for dark-matter axions
• A Search for Invisible Axion Dark Matter with the Axion Dark Matter Experiment
• One percent determination of the primordial deuterium abundance
• Revisiting the bound on axion-photon coupling from Globular Clusters
• The effects of He I 10830 on helium abundance determinations
• New Observables for Direct Detection of Axion Dark Matter
• Broadband and Resonant Approaches to Axion Dark Matter Detection
• First results from a microwave cavity axion search at 24 micro-eV
• Axion Dark Matter Detection using an LC Circuit
• A Radio for Hidden-Photon Dark Matter Detection
• An Improved RF Cavity Search for Halo Axions
• Revealing the Dark Matter Halo with Axion Direct Detection
• The HAYSTAC Axion Search Analysis Procedure
• Design and Operational Experience of a Microwave Cavity Axion Detector for the 20-100 micro-eV Range
• The Cosmic Axion Background
• Future Directions in the Microwave Cavity Search for Dark Matter Axions
• Constraints on the coupling with photons of heavy axion-like-particles from Globular Clusters
• Dark Matter Interferometry
• Axion production and detection with superconducting RF cavities
• On the Sensitivity of Spin-Precession Axion Experiments
• First Scan Search for Dark Photon Dark Matter with a Tunable Superconducting Radio-Frequency Cavity
• Development of axion haloscopes for high-mass search at CAPP