Probing sub-GeV mass SIMP dark matter with a low-threshold surface
  experiment
  Using data from the $\nu$-cleus detector, based on the surface of the Earth,
we place constraints on dark matter in the form of Strongly Interacting Massive
Particles (SIMPs) which interact with nucleons via nuclear-scale cross
sections. For large SIMP-nucleon cross sections the sensitivity of traditional
direct dark matter searches using underground experiments is limited by the
energy loss experienced by SIMPs, due to scattering with the rock overburden
and experimental shielding on their way to the detector apparatus. Hence a
surface-based experiment is ideal for a SIMP search, despite the much larger
background, resulting from the lack of shielding. We show using data from a
recent surface run of a low-threshold cryogenic detector that values of the
SIMP-nucleon cross section up to approximately $10^{-27}$ cm$^2$ can be
excluded for SIMPs with masses above 100 MeV.
