We compute the cross section for exclusive double-diffractive gamma-gamma
production at the Tevatron, ppˉ​→p+γγ+pˉ​, and
the LHC. We evaluate both the gluon-gluon and quark-antiquark t-channel
exchange contributions to the process. The observation of exclusive gamma-gamma
production at the Tevatron will provide a check on the model predictions, and
offer an opportunity to confirm the expectations for exclusive
double-diffractive Higgs production at the LHC.Comment: 16 pages, 7 figure