Diffractive Dijet Production at sqrt(s)=630 and 1800 GeV at the Fermilab Tevatron

Abstract

We report a measurement of the diffractive structure function $F_{jj}^D$ of the antiproton obtained from a study of dijet events produced in association with a leading antiproton in $\bar pp$ collisions at $\sqrt s=630$ GeV at the Fermilab Tevatron. The ratio of $F_{jj}^D$ at $\sqrt s=630$ GeV to $F_{jj}^D$ obtained from a similar measurement at $\sqrt s=1800$ GeV is compared with expectations from QCD factorization and with theoretical predictions. We also report a measurement of the $ξ$ ($x$-Pomeron) and $β$ ($x$ of parton in Pomeron) dependence of $F_{jj}^D$ at $\sqrt s=1800$ GeV. In the region $0.035<ξ<0.095$, $|t|<1$ GeV$^2$ and $β<0.5$, $F_{jj}^D(β,ξ)$ is found to be of the form $β^{-1.0\pm 0.1} ξ^{-0.9\pm 0.1}$, which obeys $β$-$ξ$ factorization.