Diffraction in hadron-hadron interactions

Results on soft and hard diffraction in $pp$ and $\bar pp$ collisions are reviewed with emphasis on factorization and scaling properties of differential cross sections. While conventional factorization breaks down at high energies, a scaling behavior emerges, which leads to a universal description of diffractive processes in terms of a (re)normalized rapidity gap probability distribution.Comment: 12 pages, Late

The diffractive structure function at the Tevatron: CDF results

Results on hard diffraction from CDF are reviewed with emphasis on the determination of the diffractive structure function of the (anti)proton from single diffractive and double Pomeron exchange dijet production. Comparison of the diffractive dijet results with predictions based on diffractive deep inelastic scattering at HERA shows a breakdown of conventional QCD factorization. A similar breakdown is observed within the CDF results in comparing the structure functions obtained from single diffraction and double Pomeron exchange.Comment: 10 pages, Late

Factorization and Scaling in Hard Diffraction

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

Multigap diffraction at CDF

We present a study of $\bar pp$ collisions with a leading antiptoton and a rapidity gap in addition to that associated with the antiproton. The second gap is either within the region available to the proton dissociation products, $\bar p+p\to (\bar p+gap)+X+gap+Y$, or adjacent to the outgoing proton $\bar p+p\to (\bar p+gap)+X+(gap+p)$. Results are reported for two-gap to one-gap event ratios and compared with one-gap to no-gap ratios and with theoretical expectations.Comment: 4 pages, LaTex; presented at Moriond-2002 for the CDF Collaboratio