Okubo-Zweig-Iizuka rule violation in photoproduction

Abstract

We investigate OZI rule violation in ω and ϕ-meson photoproduction off nucleons. Data on the total cross sections indicate a large ϕ/ω ratio of about 0.8 at the maximal available photon energy that is in good agreement with expectations from QCD. On the other hand, data at large four-momentum transfer exhibit a ratio of about 0.07, showing that the perturbative QCD regime is not approached at |t|>2 GeV2 and photon energies Eγ<4 GeV. The anomanously large ϕ/ω ratio at low energies, that is close to the reaction threshold, remains to be explained within nonperturbative QCD.