Are the AMS-02 antihelium candidate events real?
In plain words
The AMS-02 detector team has spoken of a handful of possible antihelium nuclei, which ordinary cosmic-ray collisions should almost never make. The events have not been published in a refereed paper.
Precise statement
AMS-02 has reported in conference talks a few candidate antihelium-3 and antihelium-4 events, while predicted secondary production gives far less than one antihelium-4 event in the exposure. Decide whether any candidate is a genuine antinucleus rather than a misidentified background, and if so identify its source (dark matter, antimatter domains, or underestimated coalescence production).
What would settle it
A refereed AMS-02 analysis with background estimates, or independent detection by a separate experiment such as the GAPS balloon instrument.
Status in the literature
Unverified note
As of 2026 the candidates remain unpublished in the refereed literature.