Elastic electron-nucleon scattering beyond one-photon exchange
Kobushkin
Bogolyubov Institute for Theoretical Physics Kiev, Ukraine
日時：2005年10月14日（金） 16:00-
場所：原子核理学研究施設会議室
We discuss the present situation in precision experimental study of elasticelectron-nucleon scattering, which give information about effects beyond theone-photon exchange. Such a study is important to get reliable informationon the nucleon structure at short distances. Special interest is connectedwith study of one-particle polarization observables, the beam and targetspin asymmetry. This quantities disappear in the one-photon exchange andthus give a direct information on the two-photon exchange inelectron-nucleon scattering. We give predictions for the target asymmetryand compare our theoretical results for the beam asymmetry with experimentin the resonance region (electron laboratory energy up to few GeV). Wediscuss role of large logarithms, $|n^2(Q^2/m^2)$ and $|n(Q^2/m^2)$ (where$m$ is the electron mass and -$Q^2$ is the momentum transfer squared), whichenhance the beam spin asymmetry.