Dijet cross sections in photoproduction at HERA

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 (E τ jet ). 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 E T jet > 6 GeV and of the resolved photon events with E t jet > 11 GeV. Calculated cross sections for resolved photon processes with 6 GeV < E T jet < 11 GeV lie below the data.