Physicists observe antihelium-4 nucleus, the heaviest antinucleus yet
Tuesday, March 22, 2011 - 13:30
in Physics & Chemistry
(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. Advances in accelerator and detector technology led to the first production of antihydrogen in 1995 and antihypertriton (strange antimatter) in 2010. Now, scientists with the STAR collaboration at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory have observed another state of antimatter for the first time: the antimatter helium-4 nucleus, which is the heaviest antinucleus observed so far.