Dijet Rapidity Gaps in Photoproduction from Perturbative QCD

TL;DR

This paper develops a perturbative QCD framework for analyzing dijet rapidity gaps in photoproduction, including resummation of soft gluon effects, and compares theoretical predictions with experimental data.

Contribution

It introduces a method to factorize and resum soft gluon effects in dijet rapidity gap events, providing a detailed theoretical approach and numerical predictions.

Findings

Resummed cross section depends on soft anomalous dimension matrices.

Good agreement with ZEUS data at low gap energy.

Provides a detailed analysis of color flow patterns.

Abstract

By defining dijet rapidity gap events according to interjet energy flow, we treat the photoproduction cross section of two high transverse momentum jets with a large intermediate rapidity region as a factorizable quantity in perturbative QCD. We show that logarithms of soft gluon energy in the interjet region can be resummed to all orders in perturbation theory. The resummed cross section depends on the eigenvalues of a set of soft anomalous dimension matrices, specific to each underlying partonic process, and on the decomposition of the scattering according to the possible patterns of hard color flow. We present a detailed discussion of both. Finally, we evaluate numerically the gap cross section and gap fraction and compare the results with ZEUS data. In the limit of low gap energy, good agreement with experiment is obtained.