A haloscope of the QUAX–<math><mi>a</mi><mi>γ</mi></math> experiment composed of an oxygen-free high thermal conductivity-Cu cavity inside an 8.1 T magnet and cooled to <math><mo>∼</mo><mn>200</mn><mtext> </mtext><mtext> </mtext><mi>mK</mi></math> is put in operation for the search of galactic axion with mass <math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>≃</mo><mn>43</mn><mtext> </mtext><mtext> </mtext><mi>μ</mi><mi>eV</mi></mrow></math>. 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 <math><msub><mi>ν</mi><mi>c</mi></msub><mo>=</mo><mn>10.40176</mn><mtext> </mtext><mtext> </mtext><mi>GHz</mi></math>, the experiment reaches the sensitivity necessary for the detection of galactic QCD-axion, setting the 90% confidence level limit to the axion-photon coupling <math><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>a</mi><mi>γ</mi><mi>γ</mi></mrow></msub><mo>&lt;</mo><mn>0.766</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>13</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>.

Italy

Search for invisible axion dark matter of mass <math><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>=</mo><mn>43</mn><mtext> </mtext><mtext> </mtext><mi>μ</mi><mi>eV</mi></mrow></math> with the QUAX–<math><mi>a</mi><mi>γ</mi></math> experiment