Cosmic Ray Antihelium from a Strongly Coupled Dark Sector

Standard Model extensions with a strongly coupled dark sector can induce high-multiplicity states of soft quarks. Such final states trigger extremely efficient antinucleus formation. We show that dark matter annihilation or decay into a strongly coupled sector can dramatically enhance the cosmic-ray antinuclei flux – by six orders of magnitude in the case of ${}^4\overline{\text{He}}$. In this work, we argue that the tentative ${}^3\overline{\text{He}}$ and ${}^4\overline{\text{He}}$ events reported by the AMS-02 collaboration could be the first sign of a strongly coupled dark sector observed in nature.