Search for Galactic axions with a high- Q dielectric cavity

A haloscope of the QUAX-ay experiment, composed of an high-Q resonant cavity immersed in a 8 T magnet and cooled to similar to 4.5 K is operated to search for galactic axions with mass m(a) similar or equal to 42.8 mu eV, not accessible to other running experiments. The design of the cavity with hollow dielectric cylinders concentrically inserted in a OFHC Cu cavity, allowed us to maintain a loaded quality-factor Q similar to 300000 during the measurements in presence of magnetic field. Through the cavity tuning mechanism it was possible to modulate the resonance frequency of the haloscope in the region 10.35337 - 10.35345 GHz and thus acquire different datasets at different resonance frequencies. Acquiring each datasets for about 50 minutes, combining them and correcting for the axion's signal estimation-efficiency, we set a limit on the axion-photon coupling g(alpha gamma gamma) < 0.731 x 10(-13) GeV-1 with the confidence level set at 90%.