Dijets in Diffractive Photoproduction measured with the ZEUS Experiment

Abstract

The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb^-1</nobr> of data taken with the ZEUS detector at HERA. <br /> The measurements have been made at a centre-of-mass energy &radic s =318 GeV</nobr> in the kinematic range 0.2 < y < 0.85</nobr> and x_IP < 0.025</nobr>, where y is the inelasticity and x_IP</nobr> is the fraction of the proton momentum taken by the diffractive exchange. The jets have been reconstructed using the longitudinally invariant k_T</nobr> algorithm. The two jets with the highest transversal energy have been required to satisfy E_T > 7.5</nobr> and 6.5 GeV</nobr>, respectively, and to be in the pseudorapidity range -1.5 < η < 1.5.</nobr><br /> Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations.