Hard exclusive photoproduction of $\Phi$ mesons

Abstract

We calculate the differential cross section and single-polarization observables for the reaction $\gamma p\to \Phi p$ within perturbative QCD, treating the proton as a quark-diquark system. The phenomenological couplings of gauge bosons to (spatially extended) diquarks and the quark-diquark distribution amplitude of the proton are adopted from previous investigations of baryon form factors and two-photon processes. Going beyond leading order, we take into account hadron-mass effects by means of a systematic expansion in the small parameter (hadron mass/ photon energy). With the $\Phi$-meson distribution amplitude taken from the literature our predictions for the differential cross section at $| t | \agt 4 \text{GeV}^2$ seem to provide a reasonable extrapolation of the low-t data and are also comparable in magnitude with the results of a two-gluon exchange model in which the gluons are considered as a remnant of the pomeron. For momentum transfers of a few GeV hadron-mass effects appear still to be sizeable.

37 pages, 7 figures, uses RevTeX style

References in corpus (6)

• Measurements of the Meson-Photon Transition Form Factors of Light Pseudoscalar Mesons at Large Momentum Transfer
• Nonforward parton densities and soft mechanism for form factors and wide-angle Compton scattering in QCD
• Linking Parton Distributions to Form Factors and Compton Scattering
• Photoproduction of phi mesons from the proton: Polarization observables and strangeness in the nucleon
• A perturbative approach to the eta_c-gamma transition form factor
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Cited by in corpus (3)

• Photoproduction of phi(1020) mesons on the proton at large momentum transfer
• Photoproduction of the $\omega$ meson on the proton at large momentum transfer
• Exclusive Decuplet-Baryon Pair Production in Two-Photon Collisions