Diffractive structure function in a quasiclassical approximation - art. no. 054025

We derive an expression for the diffractive F-2 structure function which sh ould be valid at small x for quasielastic scattering on a hadron and for qu asielastic scattering on a large nucleus. This expression includes multiple rescatterings of the quark-antiquark pair produced by the virtual photon o ff the sources of color charge in a quasiclassical approximation. We find t hat there is a relation between such diffractive production and inclusive p rocesses. In the former, one averages over all colors of sources before squ aring the amplitude, and in the latter one first squares the amplitude and then averages it in the hadron or nuclear wave function. We show that in th e limit of a large Virtuality of the photon Q(2) the diffractive structure function becomes linearly proportional to the gluon distribution of the had ron or nucleus, therefore proving that in this sense diffraction is a leadi ng twist effect. [S0556-2821(99)02915-X].