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Recent progress in pion photo- and electroproduction analysis

L. Tiator·D. Drechsel·S. Kamalov·S. N. Yang
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Abstract

Pion photo- and electroproduction has been studied at threshold and in the resonance region below W=2GeV. At threshold pi^0 production can be very well explained within a dynamical model derived from an effective chiral Lagrangian. The final state interaction is nearly saturated by single charge exchange rescattering. In the resonance region new electroproduction data at Q^2=1GeV^2 has been analyzed with MAID and longitudinal and transverse photon helicity amplitudes have been determined for different resonances. A detailed study of the E/M and S/M ratios of the N->Delta transition shows a zero crossing of REM near Q^2=4GeV^2, whereas the RSM becomes increasingly negative at large Q^2.

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L. Tiator, D. Drechsel, S. Kamalov, S. N. Yang. 2001-11-22. Recent progress in pion photo- and electroproduction analysis. https://arxiv.org/abs/nucl-th/0111062

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