We determine the contribution to $\mathrm{pp}\to ZZ+X$ from $\mathrm{g}\mathrm{l}\mathrm{u}\mathrm{o}\mathrm{n}+\mathrm{g}\mathrm{l}\mathrm{u}\mathrm{o}\mathrm{n}\to \mathrm{ZZ}$ by evaluating the relevant box diagrams.

• Received 1 June 1987

DOI:https://doi.org/10.1103/PhysRevD.36.1570