The Structure of Real Photons at Hera

Inclusive jet cross sections for the reaction e⁺ p → jet + X for Q² < 1 GeV² have been measured with the H1 detector at HERA. Differential cross sections as a function of η_jet and E_Tjet are in good agreement with NLO QCD calculations using different sets of photon parton density functions as input. Dijet cross sections of jets with high E_T were measured by both the ZEUS and H1 experiments in photoproduction. Comparisons of ZEUS data to NLO QCD calculations show that the theory underestimates the data for low x_γ, indicating possible inadequacies in the photon structure parametrisations. H1 data are in good agreement with the predictions of NLO QCD. The measurements were, however, made in different kinematic regions.