CAPP-8TB: Search for Axion Dark Matter in a Mass Range of 6.62 to 7.04 $\mu$eV

TL;DR

CAPP-8TB is an experimental search for axion dark matter within a specific mass range, utilizing a microwave resonant cavity, aiming to reach the sensitivity needed to detect QCD axions and improve upon previous limits.

Contribution

This paper presents the first results of the CAPP-8TB experiment and discusses upgrades to enhance sensitivity in the search for axion dark matter.

Findings

Initial results set new limits on axion-photon coupling in the targeted mass range.

The experiment approaches the sensitivity needed to detect QCD axions.

Proposed upgrades aim to improve detection sensitivity further.

Abstract

The axion is a hypothetical particle proposed to solve the strong $CP$ problem, and also a candidate for dark matter. This non-relativistic particle in the galactic halo can be converted into a photon under a strong magnetic field and detected with a microwave resonant cavity. Relying on this detection method, many experiments have excluded some mass regions with certain sensitivities in terms of axion-photon coupling ($g_{a\gamma\gamma}$) for decades, but no axion dark matter has been discovered to date. CAPP-8TB is an axion haloscope experiment at IBS/CAPP designed to search for the axion in a mass range of 6.62 to 7.04 $\mu$eV. The experiment aims for the most sensitive axion dark matter search in this particular mass range with its first-phase sensitivity reaching the QCD axion band. In this presentation, we discuss the overview of the experiment, and present the first result. We also discuss an upgrade of the experiment to achieve higher sensitivity.