  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 GeV^2, 0.20 < y < 0.85
and x_pom < 0.025, where Q^2 is the photon virtuality, y is the inelasticity
and x_pom 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.
