Dijet Cross Sections in Photoproduction at HERA

TL;DR

This paper reports measurements of dijet cross sections in photoproduction at HERA, extending previous results with higher statistics and comparing them to next-to-leading order QCD calculations, revealing areas of agreement and discrepancy.

Contribution

It provides new measurements of dijet cross sections at higher jet energies using multiple jet algorithms, enhancing the understanding of photoproduction processes at HERA.

Findings

Agreement with QCD for certain energy ranges and pseudorapidity dependence.

Discrepancies between data and theory for intermediate energy resolved photon processes.

Extended the energy range of measured cross sections with higher statistical precision.

Abstract

Dijet cross sections are presented using photoproduction data obtained with the ZEUS detector during 1994. These measurements represent an extension of previous results, as the higher statistics allow cross sections to be measured at higher jet transverse energy (ETJ). Jets are identified in the hadronic final state using three different algorithms, and the cross sections compared to complete next-to-leading order QCD calculations. Agreement with these calculations is seen for the pseudorapidity dependence of the direct photon events with ETJ > 6 GeV and of the resolved photon events with ETJ > 11 GeV. Calculated cross sections for resolved photon processes with 6 GeV < ETJ < 11 GeV lie below the data.