Exclusive photoproduction of γ: From HERA to Tevatron

The forward photoproduction amplitude for gamma p -> gamma p is calculated in a pQCD k(perpendicular to)-factorization approach with an unintegrated gluon distribution constrained by inclusive deep-inelastic structure functions. The total cross section for diffractive gamma s is compared with recent HERA data. We also discuss the 2S/1S ratio in diffractive T-production. The amplitude is used to predict the cross section for exclusive gamma production in hadronic reactions. Differential distributions for the exclusive p (p) over bar -> p gamma(p) over bar process are calculated for Tevatron energies. We also show predictions for LHC. Absorption effects are included. (C) 2008 Elsevier B.V. All rights reserved.