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Preserving the gauge invariance of meson production currents in the presence of explicit final-state interactions

Helmut Haberzettl
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Abstract

A comprehensive formalism is developed to preserve the gauge invariance of currents describing the photo- or electroproduction of mesons off the nucleon when the final-state interactions of mesons and nucleons is taken into account explicitly. Replacing exchange currents by auxiliary currents, it is found that all contributions due to explicit final-state interactions are purely transverse and do not contain a Kroll-Ruderman-type contact current. The relation of the present formulation to tree-level-type prescriptions is shown.

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Helmut Haberzettl. 2000-08-05. Preserving the gauge invariance of meson production currents in the presence of explicit final-state interactions. https://doi.org/10.1103/physrevc.62.034605

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