Exclusive annihilation p pbar -> gamma gamma in a generalized parton picture

Abstract

Exclusive proton-antiproton annihilation into two photons at large s (~10 GeV^2) and |t|,|u| ~ s can be described by a generalized parton picture analogous to the 'soft mechanism' in wide-angle real Compton scattering. The two photons are emitted in the annihilation of a single fast quark and antiquark. The matrix element describing the transition of the p-pbar system to a q-qbar pair can be related to the timelike proton elastic form factors as well as to the quark/antiquark distributions measured in inclusive deep-inelastic scattering. The reaction could be studied with the proposed 1.5-15 GeV high-luminosity antiproton storage ring (HESR) at GSI.

arXiv comment4 pages, revtex4, 3 eps figures

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Cited by in corpus (15)

• Generalized Parton Distributions
• Nucleon form-factors of the energy momentum tensor in the chiral quark-soliton model
• Quark-Hadron Duality in Electron Scattering
• Quark-hadron duality in electron scattering
• PANDA Phase One
• Hadron annihilation into two photons and backward dVCS in the scaling regime of QCD
• Dual parameterization of generalized parton distributions and description of DVCS data
• Proton-Antiproton Annihilation into a Lambda_c-Antilambda_c Pair
• The process p + pbar --> gamma + pi^0 within the handbag approch
• Polynomiality of helicity off-forward distribution functions in the chiral quark-soliton model
• Deep Virtual Compton Scattering and the Nucleon Generalized Parton Distributions
• Hard exclusive baryon-antibaryon production in 2-$\gamma$ collisions
• Generalized parton distributions and wide-angle exclusive scattering
• Exclusive two-photon annihilation at large energy or large virtuality
• Some comments on the handbag approach to wide-angle exclusive scattering