First Results from the Taiwan Axion Search Experiment with a Haloscope at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>19.6</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>μ</mml:mi><mml:mi>eV</mml:mi></mml:mrow></mml:math>
Hsin Chang, Jing-Yang Chang, Yi-Chieh Chang, Yu‐Han Chang, Yuan-Hann Chang, Chien-Han Chen, Ching-Fang Chen, Kuan-Yu Chen, Yung‐Fu Chen, Wei-Yuan Chiang, Wei-Chen Chien, Hien Thi Doan, Wei-Cheng Hung, Watson Kuo, Shou-Bai Lai, Han-Wen Liu, Min-Wei OuYang, Ping-I Wu, S. S. Yu
Abstract
This Letter reports on the first results from the Taiwan Axion Search Experiment with a Haloscope, a search for axions using a microwave cavity at frequencies between 4.707 50 and 4.798 15 GHz. Apart from the nonaxion signals, no candidates with a significance of more than 3.355 were found. The experiment excludes models with the axion-two-photon coupling $|{g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}|\ensuremath{\gtrsim}8.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$, a factor of eleven above the benchmark Kim-Shifman-Vainshtein-Zakharov model, in the mass range $19.4687<{m}_{a}<19.8436\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$. It is also the first time that a haloscope experiment places constraints on ${g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}$ in the mass region of $19.4687<{m}_{a}<19.7639\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$, reaching a sensitivity 3 orders of magnitude better than the limits obtained by nonhaloscope experiments.