We derive from first principles, as the C-invariance of the electromagnetic interaction and the crossing symmetry, the general properties of two-photon exchange in electron-proton elastic scattering. We show that the presence of this mechanism destroys the linearity of the Rosenbluth separation.
The polarisation effects sensitive to the neutron electric form factor GEn in deuteron electrodisintegration are analysed using the relativistic impulse approximation. We consider the scattering of longitudinally polarised electrons by a vector-polarised deuteron target. The high-energy neutrons (detected in coincidence, with scattered electrons) are emitted along the virtual photon momentum k . In this case the target polarisation should be orthogonal to k and must lie (in coplanar geometry) in the y*d+np reaction plane, y* being the virtual photon. If the target polarisation is orthogonal to the reaction plane, then in order to determine G,,, it is necessary to study the 9 dependence of the corresponding asymmetry. Some polarisation components of high-energy neutrons produced in disintegration of unpolarised deuterons by longitudinally polarised electrons are also sensitive to GEn.
The possible contribution of two-photon exchange to electron deuteron elastic scattering at relatively high momentum transfer is discussed. This study was motivated by the high precision data recently obtained at the Jefferson Laboratory. Using general arguments, based on crossing symmetry for the processes e Ϫ ϩh→e Ϫ ϩh and e ϩ ϩe Ϫ →hϩh , we find a parametrization for the angular dependence of the interference between the one-and two-photon exchanges in the differential cross section for elastic ed scattering in terms of a new kinematical variable and compare our findings to the recent data.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.