arXiv:hep-ph/0404206·v1·High Energy Physics — Phenomenology
Beam normal spin asymmetry in elastic lepton-nucleon scattering
M. Gorchtein🇮🇹 · P.A.M. Guichon🇫🇷 · M. Vanderhaeghen🇺🇸
Abstract
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 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.
Comments: 17 pages, 5 figures