Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

Abstract

Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7~GeV at a proton scattering angle of \cma$=70^{\circ }$. The longitudinal transfer \KLL, measured to be $0.645\pm 0.059\pm 0.048$, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is $\sim$3~times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

6 pages, 5 figures, the text has been made consistent with the published

References in corpus (2)

• Flavor decomposition of the elastic nucleon electromagnetic form factors
• Compton Scattering Cross Section on the Proton at High Momentum Transfer

Cited by in corpus (7)

• Exclusive Meson Photo- and Electro-production, a Window on the Structure of Hadronic Matter
• Determination of generalized parton distributions through a simultaneous analysis of axial form factor and wide-angle Compton scattering data
• Twist-3 contributions to wide-angle photoproduction of pions
• The GPD H-tilde and spin correlations in wide-angle Compton scattering
• Wide-angle photo- and electroproduction of pions to twist-3 accuracy
• The Constituent Counting Rule and Omega Photoproduction
• Compton scattering in the Endpoint Model