seminar

Run II Results on Diffraction from CDF

Abstract

High-energy diffraction has sparkled great interest in recent years due to HERA and Tevatron data, helping pave the way to a better understanding of the pomeron in the framework of perturbative QCD. The results obtained at the Tevatron have provided a comprehensive view of diffractive physics.
   The signature of a typical diffractive event in $p\overline{p}$ collisions is characterized by a leading proton or antiproton and/or a region at large pseudorapidity with no particles, also known as {\it rapidity gap}. Hard diffraction processes are hadronic interactions that
incorporate a high transverse momentum partonic scattering, while carrying the characteristic signature of a diffractive event.
   At the Tevatron, the CDF experiment has reported a number of diffractive studies. These measurements can now be extended with larger data samples, new triggers, and improved detectors. We report new updated results on diffraction obtained by CDF from data collected during Run II of the Fermilab Tevatron $\bar pp$ collider operating at
$\sqrt s$=1.96 GeV.
   An upgraded forward detector system and a larger integrated luminosity have extended the reach of the CDF hard diffraction program to higher $Q²$ and lower $\xi$ (fractional momentum loss of leading nucleon). The $Q²$ dependence of the diffractive structure function of the nucleon will be presented, as well as results from a study of
exclusive production of dijet and low-mass states.