Handling the Handbag Diagram in Compton Scattering on the Proton

Abstract

Poincare invariance, gauge invariance, conservation of parity and time reversal invariance are respected in an impulse approximation evaluation of the handbag diagram. Proton wave functions, previously constrained by comparison with measured form factors, that incorporate the influence of quark transverse and orbital angular momentum (and the corresponding violation of proton helicity conservation) are used. Computed cross sections are found to be in reasonably good agreement with early measurements. The helicity correlation between the incident photon and outgoing proton, $K_{LL}$, is both large and positive at back angles. For photon laboratory energies of $\le$ 6 GeV, we find that $K_{LL}\ne A_{LL}$, $D_{LL}\ne 1$, and that the polarization $P$ can be large.

9 pages, 6 figures. Replacement fixes some typos, improves references and figures. An error in Fig. 6 was corrected and related comments in the text changed

References in corpus (2)

• Generalized Parton Distributions
• Light Front Cloudy Bag Model: Nucleon Electromagnetic Form Factors

Cited by in corpus (11)

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• The GPD H-tilde and spin correlations in wide-angle Compton scattering
• Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton
• QCD radiative corrections to the soft spectator contribution in the wide angle Compton scattering
• Generalized perton distributions: analysis and applications
• Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles
• Some comments on the handbag approach to wide-angle exclusive scattering