Phys. Rev. D 72, 013008 (2005) [18 pages]Two-photon exchange contribution to elastic electron-nucleonscattering at large momentum transferReceived 2 February 2005; published 28 July 2005 We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide-angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments. Two-photon exchange has additional consequences which could be experimentally observed, including nonzero polarization effects and a positron-proton/electron-proton scattering asymmetry. The predicted Rosenbluth plot is no longer precisely linear; it acquires a measurable curvature, particularly at large laboratory angle. © 2005 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevD.72.013008
DOI:
10.1103/PhysRevD.72.013008
PACS:
25.30.Bf, 13.40.Gp, 24.85.+p
|
|
About | Terms and Conditions | Subscriptions | Search | Help
Use of the American Physical Society websites and journals implies that the user has read and agrees to our Terms and Conditions and any applicable Subscription Agreement. Physical Review®, Physical Review Letters®, Reviews of Modern Physics®, and Physical Review Special Topics® are trademarks of the American Physical Society.