Hadrophilic Light Dark Matter from the Atmosphere
  Light sub-GeV dark matter (DM) constitutes an underexplored target, beyond
the optimized sensitivity of typical direct DM detection experiments. We
comprehensively investigate hadrophilic light DM produced from cosmic-ray
collisions with the atmosphere. The resulting relativistic DM, originating from
meson decays, can be efficiently observed in variety of experiments, such as
XENON1T. We include for the first time decays of $\eta$, $\eta^{\prime}$ and
$K^+$ mesons, leading to improved limits for DM masses above few hundred MeV.
We incorporate an exact treatment of the DM attenuation in Earth and
demonstrate that nuclear form factor effects can significantly impact the
resulting testable DM parameter space. Further, we establish projections for
upcoming experiments, such as DARWIN, over a wide range of DM masses below the
GeV scale.
