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. The longitudinal transfer \KLL, measured to be , 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 3~times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
Keywords
Cite
@article{arxiv.1506.04045,
title = {Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton},
author = {C. Fanelli and E. Cisbani and D. J. Hamilton and G. Salme and B. Wojtsekhowski and A. Ahmidouch and J. R. M. Annand and H. Baghdasaryan and J. Beaufait and P. Bosted and E. J. Brash and C. Butuceanu and P. Carter and E. Christy and E. Chudakov and S. Danagoulian and D. Day and P. Degtyarenko and R. Ent and H. Fenker and M. Fowler and E. Frlez and D. Gaskell and R. Gilman and T. Horn and G. M. Huber and C. W. de Jager and E. Jensen and M. K. Jones and A. Kelleher and C. Keppel and M. Khandaker and M. Kohl and G. Kumbartzki and S. Lassiter and Y. Li and R. Lindgren and H. Lovelace and W. Luo and D. Mack and V. Mamyan and D. J. Margaziotis and P. Markowitz and J. Maxwell and G. Mbianda and D. Meekins and M. Meziane and J. Miller and A. Mkrtchyan and H. Mkrtchyan and J. Mulholland and V. Nelyubin and L. Pentchev and C. F. Perdrisat and E. Piasetzky and Y. Prok and A. J. R. Puckett and V. Punjabi and M. Shabestari and A. Shahinyan and K. Slifer and G. Smith and P. Solvignon and R. Subedi and F. R. Wesselmann and S. Wood and Z. Ye and X. Zheng},
journal= {arXiv preprint arXiv:1506.04045},
year = {2015}
}
Comments
6 pages, 5 figures, the text has been made consistent with the published