Factorization and Non-factorization in Diffractive Hard Scattering

Factorization, in the sense defined for inclusive hard scattering, is discussed for diffractive hard scattering. A factorization theorem similar to its inclusive counterpart is presented for diffractive DIS. For hadron-hadron diffractive hard scattering, in contrast to its inclusive counterpart, the expected breakdown of factorization is discussed. Cross section estimates are given from a simple field theory model for non-factorizing double-pomeron-exchange (DPE) dijet production with and without account for Sudakov suppression. To appear in DIS 97 proceedings, ed. J. O. Repond In the general phenomena of diffractive hard scattering, the initial proton in DIS or both protons at hadron collider participate in a hard process involving a very large momentum transfer, but one or at hadron colliders one or both hadrons is diffractively scattered, emerging with a small transverse momentum and the loss of a rather small fraction of longitudinal momentum. In this talk I will discuss the factorization theorem of diffractive DIS and its expected breakdown in hadronhadron initiated diffractive hard processes. Following [1], I will formulate the hypothesis of diffractive factorization in two step. In the first stage we hypothesize that the diffractive structure function F diff 2 can be written in terms of a diffractive parton distribution : dF diff 2 (βxIP , Q ; xIP , t) dxIP dt = xIP ∑