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Polarization phenomena in elastic $e^{\mp}N$ scattering, for axial parametrization of two-photon exchange

M. P. Rekalo·E. Tomasi-Gustafsson
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Abstract

We analyze polarization phenomena for elastic lepton-nucleon scattering, parametrizing the $2γ$-exchange contribution, as the product of lepton and nucleon axial vector currents, that correspond to $C=+1$ exchange in the annihilation channel. We found two combinations of polarization observables (one for three T-odd observables and another one - for five T-even observables), which allow to measure the ratio $G_E(Q^2)/G_M(Q^2)$ of nucleon electromagnetic form factors in model independent way, without any specific assumption about the $2γ$-exchange mechanism. Both these combinations have a general character and do not depend on the choice of the spin structure for the $2γ$-exchange. We show the inconsistency of other approximations recently used in the literature.

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M. P. Rekalo, E. Tomasi-Gustafsson. 2004-02-02. Polarization phenomena in elastic $e^{\mp}N$ scattering, for axial parametrization of two-photon exchange. https://doi.org/10.1016/j.nuclphysa.2004.07.009

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