Eighteen examples of the heaviest antiparticle ever found, the nucleus of antihelium-4, have been made in the STAR experiment at Brookhaven’s Relativistic Heavy Ion Collider. STAR already held the record for the heaviest antiparticle, an “antihypertriton” made of three baryons, but with four baryons, antihelium was a thousand times harder to detect and is likely to hold the record for a very long time. The STAR experiment originated at Berkeley Lab; its spokesperson is Nu Xu of the Nuclear Science Division. Its Time Projection Chamber, a type of detector invented by David Nygren of the Physics Division, was designed and built here and flown to Brookhaven in a C5A. More>