Investigation of - and Odderon Induced Photoproduction of Mesons Decaying to Purely Photonic Final States at Hera

Cross section measurements made with the H1 detector at HERA are reported for the reactions γp → ωp and γp → (ωπ⁰)X, and on searches for the reactions γp → π⁰N*, γp → f₂(1270)X, and γ p -> a⁰₂(1320)X, where N* denotes an excited nucleon state. The average photon - proton centre-of-mass energies at HERA were <W> = 200 GeV and 215 GeV. Cross sections for the Pomeron -mediated reactions were determined in agreement with previous measurements and theoretical expectations. Processes mediated by Odderon - photon fusion could not be observed; upper limits on cross sections are below predictions from a non-perturbative QCD model.