Physicists observe antihelium-4 nucleus, the heaviest antinucleus yet

(PhysOrg.com) — In 1932, scientists observed the first antimatter particle, a positron (or antielectron). Since then, scientists have observed heavier and heavier states of antimatter: antiprotons and antineutrons in 1955, followed by antideuterons, antitritons, and antihelium-3 during the next two decades

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Physicists observe antihelium-4 nucleus, the heaviest antinucleus yet