This Letter reports results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 μeV. The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at sub-kelvin temperatures, thereby reducing thermal noise as well as the excess noise from the ultra-low-noise SQUID amplifier used for the signal power readout. Ongoing searches will provide nearly definitive tests of the invisible axion model over a wide range of axion masses.
@article{arxiv.1804.05750,
title = {A Search for Invisible Axion Dark Matter with the Axion Dark Matter Experiment},
author = {N. Du and N. Force and R. Khatiwada and E. Lentz and R. Ottens and L. J Rosenberg and G. Rybka and G. Carosi and N. Woolett and D. Bowring and A. S. Chou and A. Sonnenschein and W. Wester and C. Boutan and N. S. Oblath and R. Bradley and E. J. Daw and A. V. Dixit and J. Clarke and S. R. O'Kelley and N. Crisosto and J. R. Gleason and S. Jois and P. Sikivie and I. Stern and N. S. Sullivan and D. B. Tanner and G. C. Hilton},
journal= {arXiv preprint arXiv:1804.05750},
year = {2018}
}