Limits on Dark Photons, Scalars, and Axion-Electromagnetodynamics with The ORGAN Experiment

TL;DR

The ORGAN experiment has set new limits on axion and dark photon dark matter candidates using a cryogenic resonant cavity, demonstrating sensitivity to multiple dark matter types and projecting future detection capabilities.

Contribution

This paper reports the first phase results of the ORGAN axion haloscope, establishing the most stringent limits on axion-photon coupling and exploring sensitivity to dark photons and other dark matter candidates.

Findings

Set new limits on axion-photon coupling at 65 μeV.

Achieved the most sensitive dark photon exclusion limits in some parameter regions.

Projected future sensitivity for additional phases of the ORGAN experiment.

Abstract

Axions are a well-motivated dark matter candidate, with a host of experiments around the world searching for direct evidence of their existence. The ORGAN Experiment is a type of axion detector known as an axion haloscope, which takes the form of a cryogenic resonant cavity embedded in a strong magnetic field. ORGAN recently completed Phase 1a, a scan for axions around 65 \textmu eV, and placed the most stringent limits to date on the dark matter axion-photon coupling in this region, $|g_{a\gamma\gamma}|\leq 3\times 10^{-12}$. It has been shown that axion haloscopes such as ORGAN are automatically sensitive to other kinds of dark matter candidates, such as dark photons, scalar field/dilaton dark matter, and exotic axion-electromagnetic couplings motivated by quantum electromagnetodynamics. We compute the exclusion limits placed on these various dark matter candidates by ORGAN 1a, and project sensitivity for some future ORGAN phases. In particular, the dark photon limits are the most sensitive to date in some regions of the parameter space.