Normal Spin Asymmetries in Elastic Electron-Proton Scattering

✍ Scribed by M. Gorchtein; P.A.M. Guichon; M. Vanderhaeghen

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 284 KB
• Volume: 755
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/j.nuclphysa.2005.03.026

✦ Synopsis

We discuss the two-photon exchange contribution to observables which involve lepton helicity flip in elastic lepton-nucleon scattering. This contribution is accessed through the single spin asymmetry for a lepton beam polarized normal to the scattering plane. We estimate this beam normal spin asymmetry at large momentum transfer using a parton model and we express the corresponding amplitude in terms of generalized parton distributions. We further discuss this observable in the quasi-RCS kinematics which may be dominant at certain kinematical conditions and find it to be governed by the photon helicity-flip RCS amplitudes.