Collider offers new evidence for five-part particles
Quarks, the elementary units of matter found in every atomic nucleus, are surprisingly comfortable in large crowds.
Two particles discovered at the Large Hadron Collider, or LHC, near Geneva are each composed of five quarks, researchers report online July 13 at arXiv.org. Until recently, quarks had only been found in pairs or trios. Now, in just over a year, an experiment called LHC beauty has exposed a four-quark particle (SN: 5/17/14, p. 12) and two five-quark ones.
The fresh evidence for the existence of five-quark particles, or pentaquarks, is “far more compelling” than a controversial claim made a decade ago (SN: 5/14/05, p. 318), says Curtis Meyer, a particle physicist at Carnegie Mellon University in Pittsburgh.