  Diffractive scattering involves exchange of a Pomeron to make a rapidity gap.
It is normally assumed that to get a hard scattering in diffraction, one may
treat the Pomeron as an ordinary particle, which has distributions of gluons
and quarks. We show that this is not so: When we use perturbative QCD, there is
a breakdown of the factorization theorem. The whole Pomeron can initiate the
hard scattering, even though it is not point-like. Qualitatively, but not
quantitatively, this gives the same effect as a delta function term in the
gluon density in a Pomeron.
