2021 Impact factor 3.131
Hadrons and Nuclei
Open Access
Eur. Phys. J. A 24, s2.23-s2.27 (2005)
DOI: 10.1140/epjad/s2005-04-004-4

Two photon effects in electron scattering

P.A.M. Guichon

SPhN/DAPNIA, CEA Saclay, F91191 Gif sur Yvette, France

(Received 15 November 2004 / Published online 08 February 2005)


The apparent discrepancy between the Rosenbluth and the polarization transfer method for the ratio of the electric to magnetic proton form factors can be explained by a two-photon exchange correction which does not destroy the linearity of the Rosenbluth plot. Though intrinsically small, of the order of a few percent of the cross section, this correction is kinematically enhanced in the Rosenbluth method while it is small for the polarization transfer method, at least in the range of Q2 where it has been used until now.

PACS: 25.30.Bf Elastic electron scattering - 13.40.Gp Electromagnetic form factors - 24.85.+p Quarks, gluons, and QCD in nuclei and nuclear processes

© Società Italiana di Fisica, Springer-Verlag 2005