Two-photon exchange contribution in elastic electron-proton scattering, experiment at the VEPP-3 storage ring
1 Budker Institute of Nuclear Physics of SB RAS, 630090 Novosibirsk, Russia
2 Argonne National Laboratory, Argonne, Illinois 60439, USA
3 Novosibirsk State University, 630090 Novosibirsk, Russia
4 Nuclear Physics Institute of Tomsk Polytechnic University, 634050 Tomsk, Russia
5 NIKHEF, P.O. Box 41882, 1009 DB Amsterdam, The Netherlands
a e-mail: D.M.Nikolenko@inp.nsk.su
Published online: 20 March 2014
We describe a precise measurement of the ratio of the (e+ p) to (e− p) elastic scattering cross sections. This comparison is sensitive to the effect of two-photon exchange contributions which may be the cause for inconsistent extractions of the proton form factors obtained using different methods. The experiment was performed at storage ring VEPP–3, Novosibirsk at energies of positron/electron beams of 1.0 and 1.6 GeV with electron/positron scattering angles θ = 65÷105° for the first case and 15÷25° and 55÷75° for the second case. Details of the experiment and the preliminary results are presented.
© Owned by the authors, published by EDP Sciences, 2014
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