Projected sensitivity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mtext>DMRadio-m</mml:mtext></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>: A search for the QCD axion below <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>1</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi mathvariant="normal">μ</mml:mi><mml:mi>eV</mml:mi></mml:mrow></mml:math>
Lucas Brouwer, Saptarshi Chaudhuri, H.-M. Cho, J. Corbin, W. Craddock, C Dawson, A. Droster, Joshua W. Foster, J. Fry, Peter W. Graham, R. Henning, K. D. Irwin, F. Kadribasic, Yonatan Kahn, Aya Keller, R. Kolevatov, Stephen E. Kuenstner, A. Leder, D. Li, Jonathan Ouellet, K. M. W. Pappas, A. Phipps, N. M. Rapidis, Benjamin R. Safdi, Chiara P. Salemi, Maria Simanovskaia, J. Singh, E. C. van Assendelft, K. van Bibber, K. Wells, L. A. Winslow, W. J. Wisniewski, Betty Young
Abstract
The QCD axion is one of the most compelling candidates to explain the dark matter abundance of the Universe. With its extremely small mass ($\ensuremath{\ll}1\text{ }\text{ }\mathrm{eV}/{c}^{2}$), axion dark matter interacts as a classical field rather than a particle. Its coupling to photons leads to a modification of Maxwell's equations that can be measured with extremely sensitive readout circuits. ${\text{DMRadio-m}}^{3}$ is a next-generation search for axion dark matter below $1\text{ }\text{ }\mathit{\ensuremath{\mu}}\mathrm{eV}$ using a $>4\text{ }\text{ }\mathrm{T}$ static magnetic field, a coaxial inductive pickup, a tunable LC resonator, and a DC-SQUID readout. It is designed to search for QCD axion dark matter over the range $20\text{ }\text{ }\mathrm{neV}\ensuremath{\lesssim}{m}_{a}{c}^{2}\ensuremath{\lesssim}800\text{ }\mathrm{neV}$ ($5\text{ }\text{ }\mathrm{MHz}<\ensuremath{\nu}<200\text{ }\mathrm{MHz}$). The primary science goal aims to achieve Dine-Fischler-Srednicki-Zhitnitsky sensitivity above ${m}_{a}{c}^{2}\ensuremath{\approx}120\text{ }\text{ }\mathrm{neV}$ (30 MHz), with a secondary science goal of probing Kim-Shifman-Vainshtein-Zakharov axions down to ${m}_{a}{c}^{2}\ensuremath{\approx}40\text{ }\text{ }\mathrm{neV}$ (10 MHz).