Dark Matter Annihilation Can Produce a Detectable Antihelium Flux through <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mover accent="true"><mml:mi mathvariant="normal">Λ</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mi>b</mml:mi></mml:msub></mml:math> Decays
Martin Wolfgang Winkler, Tim Linden
Abstract
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 Λ[over ¯]_{b}-baryons-can significantly boost the dark matter induced antihelium flux. This process can entirely dominate the production of high-energy antihelium nuclei, increasing the rate of detectable AMS-02 events by 2 orders of magnitude.