Pi0 photo- and electroproduction at threshold within a dynamical model

Abstract

We show that, within a meson-exchange dynamical model describing most of the existing pion electromagnetic production data up to the second resonance region, one is also able to obtain a good agreement with the pi0 photo- and electroproduction data near threshold. The potentials used in the model are derived from an effective chiral Lagrangian. The only sizable discrepancy between our results and the data is in the P-wave amplitude P3 = 2M1+ + M1-, where our prediction underestimate the data by about 20%. In the case of pi0 production, the effects of final state interaction in the threshold region are nearly saturated by single charge exchange rescattering. This indicates that in ChPT it might be sufficient to carry out the calculation just up to one-loop diagrams for threshold neutral pion production.

10 pages LATEX including 7 figures and 3 tables (minor textual changes and new Fig. 5)

References in corpus (3)

• Pion cloud and the $Q^2-$dependence of ${\gamma }^{\ast }N\leftrightarrow \Delta$ transition form factors
• Pion-nucleon interaction in a covariant hadron-exchange model
• Meson-exchange $\pi N$ Models in Three-Dimensional Bethe-Salpeter Formulation

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