Light Dark Matter Search with a High-Resolution Athermal Phonon Detector
  Operated Above Ground
  We present limits on spin-independent dark matter-nucleon interactions using
a $10.6$ $\mathrm{g}$ Si athermal phonon detector with a baseline energy
resolution of $\sigma_E=3.86 \pm 0.04$ $(\mathrm{stat.})^{+0.19}_{-0.00}$
$(\mathrm{syst.})$ $\mathrm{eV}$. This exclusion analysis sets the most
stringent dark matter-nucleon scattering cross-section limits achieved by a
cryogenic detector for dark matter particle masses from $93$ to $140$
$\mathrm{MeV}/c^2$, with a raw exposure of $9.9$ $\mathrm{g}\cdot\mathrm{d}$
acquired at an above-ground facility. This work illustrates the scientific
potential of detectors with athermal phonon sensors with eV-scale energy
resolution for future dark matter searches.
