Pentaquarks - A New Addition to Particle Physics

Pentaquarks are just what they sound like, five-quark baryons. The particles were very recently discovered at the CERN Large Hadron Collider, but have caused havoc with many particle physics. This is because they massive hadrons are in direct violation of quantum chromodynamics (QCD), a major part of the standard model. This system deems that particles that interact with the strong force can exist either as a quark-antiquark pair (meson) or as a three-quark particle (baryon) as all hadrons must be color-neutral.