Editing Quantum chromodynamics (section)

===Dynamics===
According to the rules of [[quantum field theory]], and the associated [[Feynman diagram]]s, the above theory gives rise to three basic interactions: a quark may emit (or absorb) a gluon, a gluon may emit (or absorb) a gluon, and two gluons may directly interact. This contrasts with [[quantum electrodynamics|QED]], in which only the first kind of interaction occurs, since [[photon]]s have no charge. Diagrams involving [[Faddeev–Popov ghost]]s must be considered too (except in the [[unitarity gauge]]).