First axion dark matter search with toroidal geometry

Abstract

We first report an axion haloscope search with toroidal geometry. In this pioneering search, we exclude the axion-photon coupling ga.. down to about 5 x 10(-8) GeV-1 over the axion mass range from 24.7 to 29.1 mu eV at a 95% confidence level. The prospects for axion dark matter searches with larger scale toroidal geometry are also considered.