Dark Matter Annihilation Can Produce a Detectable Antihelium Flux
  through $\bar{\Lambda}_b$ Decays
  Recent observations by the Alpha Magnetic Spectrometer (AMS-02) have
tentatively detected a handful of cosmic-ray antihelium events. Such events
have long been considered as smoking-gun evidence for new physics, because
astrophysical antihelium production is expected to be negligible. However, the
dark-matter-induced antihelium flux is also expected to fall below current
sensitivities, particularly in light of existing antiproton constraints. Here,
we demonstrate that a previously neglected standard model process -- the
production of antihelium through the displaced-vertex decay of
$\bar{\Lambda}_b$-baryons -- can significantly boost the dark matter induced
antihelium flux. This process can triple the standard prompt-production of
antihelium, and more importantly, entirely dominate the production of the
high-energy antihelium nuclei reported by AMS-02.
