Search for invisible axion dark matter of mass ma=43 μeV with the QUAX- aγ experiment

Abstract

A haloscope of the QUAX-aγ experiment composed of an oxygen-free high thermal conductivity-Cu cavity inside an 8.1 T magnet and cooled to ∼200 mK is put in operation for the search of galactic axion with mass ma≃43 μeV. The power emitted by the resonant cavity is amplified with a Josephson parametric amplifier whose noise fluctuations are at the standard quantum limit. With the data collected in about 1 h at the cavity frequency νc=10.40176 GHz, the experiment reaches the sensitivity necessary for the detection of galactic QCD-axion, setting the 90% confidence level limit to the axion-photon coupling gaγγ<0.766×10-13 GeV-1.