New heaviest exotic antimatter nucleus

Scientists studying the tracks of particles streaming from six billion collisions of atomic nuclei at the Relativistic Heavy Ion Collider (RHIC) — an ‘atom smasher’ that recreates the conditions of the early universe — have discovered a new kind of antimatter nucleus, the heaviest ever detected. Composed of four antimatter particles — an antiproton, two antineutrons, and one antihyperon — these exotic antinuclei are known as antihyperhydrogen-4.