The ORGAN Experiment: An axion haloscope above 15 GHz

Abstract

We present first results and future plans for the Oscillating Resonant Group AxioN (ORGAN) experiment, a microwave cavity axion haloscope situated in Perth, Western Australia designed to probe for high mass axions motivated by several theoretical models. The first stage focuses around 26.6 GHz in order to directly test a claimed result, which suggests axions exist at the corresponding mass of $110\mu$eV. Later stages will move to a wider scan range of 15-50 GHz ($60-210\mu$eV). We present the results of the pathfinding run, which sets a limit on $g_{a\gamma \gamma }$ of $2.02\times 10^{-12}$eV${}^{-1}$ at 26.531 GHz, or 110~$\mu$eV, in a span of 2.5 neV (shaped by the Lorentzian resonance) with $90\%$ confidence. Furthermore, we outline the current design and future strategies to eventually attain the sensitivity to search for well known axion models over the wider mass range.

15 pages, 5 figures. V2: As published in Physics of Dark Universe