Diffractive photoproduction of dijets in ep collisions at HERA

Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb(-1). The measurements were made in the kinematic range Q(2) < 1 GeV2, 0.20 < y < 0.85 and x(IP) < 0.025, where Q(2) is the photon virtuality, y is the inelasticity and x(IP) is the fraction of the proton momentum taken by the diffractive exchange. The two jets with the highest transverse energy, E-T(jet), were required to satisfy E-T(jet) > 7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5 < eta(jet) < 1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton.