Probabilities of rapidity gaps in high energy interactions

We show that high energy hadronic reactions which contain a rapidity gap an d a hard subprocess have a specific dependence on the kinematic variables, which results in a characteristic behaviour of the survival probability of the gap. We incorporate this mechanism in a two-channel eikonal model to ma ke an essentially parameter-free estimate of diffractive dijet production a t the Tevatron, given the diffractive structure functions measured at HERA. The estimates are in surprising agreement with the measurements of the CDF collaboration. We briefly discuss the application of the model to other ha rd processes with rapidity gaps.