Feynman diagram

This is an example of a Feynman diagram. Here, an electron and a positron are anihilating. They produce a photon which is represetned by the blue sine wave. The photon then becomes a quark and antiquark pair, while the antiquark radiates a gluon, represented by the green helix. 

Feynman diagrams are pictorial diagrams of mathematical expressions that describe the behavior and interaction of subatomic particles. They are named for the one who introduced them in 1948: the American physicist Richard Feynman.