Search for "Invisible" Axion Dark Matter in the $3.3\text{-}4.2~{\mu}$eV
  Mass Range
  We report the results from a haloscope search for axion dark matter in the
$3.3\text{-}4.2~{\mu}$eV mass range. This search excludes the axion-photon
coupling predicted by one of the benchmark models of "invisible" axion dark
matter, the KSVZ model. This sensitivity is achieved using a large-volume
cavity, a superconducting magnet, an ultra low noise Josephson parametric
amplifier, and sub-Kelvin temperatures. The validity of our detection procedure
is ensured by injecting and detecting blind synthetic axion signals.
