Diffractive Dijet Production in Antiproton-Proton Collisions at $\sqrt{s}$=1.96 TeV

TL;DR

This study measures diffractive dijet production in proton-antiproton collisions at 1.96 TeV, analyzing event ratios and distributions to understand diffraction dynamics and their dependence on kinematic variables.

Contribution

It provides the first detailed measurement of the ratio of single-diffractive to inclusive dijet events as a function of Bjorken-$x$ and $Q^2$ at Tevatron energies, revealing weak dependencies.

Findings

Weak $x^{ar p}_{Bj}$ and $Q^2$ dependencies in event ratios

No significant $Q^2$ dependence in $t_{ar p}$ distributions

Comparison with inclusive diffraction dissociation shows similar $t_{ar p}$ behavior.

Abstract

We report on a study of diffractive dijet production in $\bar{p}p$ collisions at $\sqrt{s}=1.96$ TeV using the CDF II detector at the Fermilab Tevatron $\bar{p}p$ collider. A data sample from 310 pb$^{-1}$ of integrated luminosity collected by triggering on a high transverse energy jet, $E_T^{jet}$, in coincidence with a recoil antiproton detected in a Roman pot spectrometer is used to measure the ratio of single-diffractive to inclusive-dijet event rates as a function of $x^{\bar p}$ of the interacting parton in the antiproton, the Bjorken-$x$, $x^{\bar p}_{Bj}$, and a $Q^2\approx (E_T^{jet})^2$ in the ranges $10^{-3}<x^{\bar p}_{Bj}<10^{-1}$ and $10^2<Q^2 <10^4$ GeV$^2$, respectively. Results are presented for the region of $\bar p$-momentum-loss fraction $0.03<\xi_{\bar p}<0.09$ and a four-momentum transfer squared $t_{\bar p}>-4$ GeV$^2$. The $t_{\bar p}$ dependence is measured as a function of $Q^2$ and $x_{Bj}^{\bar p}$ and compared with that of inclusive single diffraction dissociation. We find weak $x^{\bar p}_{Bj}$ and $Q^2$ dependencies in the ratio of single diffractive to inclusive event rates, and no significant $Q^2$ dependence in the diffractive $t_{\bar p}$ distributions.