We compare results on diffractive W-boson production at the Tevatron with
predictions based on the diffractive structure function measured in deep
inelastic scattering at HERA assuming (a) conventional factorization or (b)
hard factorization combined with a rapidity gap distribution scaled to the
total gap probability. We find that conventional factorization fails, while the
scaling prediction agrees with the data.Comment: 6pp, LaTex file, uses psfig, 1 PS figure, presented at DIS9