Physicists on CERN’s LHCb collaboration say they’ve observed three new exotic particles – X(4274), X(4500) and X(4700) – and also confirmed the existence of a fourth one, X(4140). According to the scientists, each of these particles contains two quarks and two antiquarks. View of the LHCb detector. Image credit: CERN. The quark model, proposed in 1964 by Murray Gell-Mann and George Zweig, is the most valid classification scheme of hadrons...
