Physics Motivation Summary

The dramatically expanding field of hard diffraction has been driven by experimental results and experiment should continue to lead theory. More precise results are needed to improve the understanding of the nature and structure of the pomeron and distinguish between different theoretical models. There is a rich, timely program of physics that can be accessed with the addition of the FPD to the DØ detector. This includes

• Studies of pomeron structure using diffractive jet production, including the dependence on and |t|.
• Search for diffractive production of heavy objects and combining different hard diffractive channels to determine the quark and gluon content of the pomeron.
• Search for the super-hard pomeron.
• Studies of double pomeron exchange.
• Search for ``new physics'' such as glueballs, centauros, and Higgs bosons.
• Determination of pomeron universality in conjunction with HERA results.

The understanding of strong interactions is incomplete without inclusion of soft and hard diffractive processes. The Tevatron is the ideal collider to study this physics due to the large center-of-mass energy available, and the addition of the FPD will greatly augment the physics possibilities of the DØ detector.