For the first time, the LHCb collaboration at CERN has observed an exotic particle made up of four charm quarks.
tetraquark
Researchers found four new particles made of the same four building blocks.
From ars technica, Feb. 29, 2016: Fermilab’s found a brand-new species—the first particle with four flavors of quarks.
From IFL Science, Feb. 27, 2016: Scientists on the DZero experiment have found an incredible new particle that’s part of the exotic family of tetraquarks.
From Scientific American, Feb. 26, 2016: Evidence for a never-before-seen particle containing four types of quark has shown up in data from the Tevatron collider at Fermilab.
From Gizmodo, Feb. 25, 2016: Physicists from the DZero collaboration have announced the discovery of a new particle, believed to be part of an exotic family called “tetraquarks.”
DZero announces the newest member of the tetraquark family.
DZero discovers a new, exotic particle made up of four different quarks.