Large transverse momentum direct photon production in the coherent diffractive processes at hadron colliders

Direct photon production at large transverse momentum in the coherent diffractive processes at hadron colliders is calculated in the two-gluon exchange model. We find that the amplitude for the production process is related to the differential off-diagonal gluon distribution function in the proton. We estimate the production rate at the Fermilab Tevatron by approximately using the usual gluon distribution function. Because of the clean signature, this process can be used to detailed study the small-x physics, and the coherent diffractive processes at hadron colliders.