First Observation of Antihelium� - Technology Review

First Observation of Antihelium� - Technology Review: What's important about this observation is that antihelium-4 seems to occur at exactly the rate predicted by thermodynamics. So unless there's some other mechanism for making it in vastly greater quantities, we're unlikely to see a naturally occurring version, no matter how hard we look.

So "any observation of antihelium or even heavier antinuclei in space would indicate the existence of a large amount of antimatter elsewhere in the Universe," say the STAR collaboration.