ANTIMATTER COSMIC RAYS. “The detection of anti-4He or heavier antinuclei in CRs would shatter our current understanding of early Universe physics with broad cosmological implications or reveal something completely unforeseen in the realm of astrophysics, such as e.g. an anomalous abundance of dense antibaryon stars or anti-cloudlets in our Galaxy.” (CR = cosmic rays).
https://link.springer.com/content/pdf/10.1007/s10686-021-09708-w.pdf