Quartic gauge boson coupling

When four gauge bosons interact with each other, the strength of this interaction is known as the "quartic gauge boson coupling". This parameter is represented in Feynman diagrams by a vertex where four gauge boson lines meet.

The figure shows quark-quark interaction, where one virtual W boson decays into three W bosons; the convergence of the interaction lines is the “quartic gauge boson coupling”.

quarctic gauge boson coupling