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Gauge-invariant theory of pion photoproduction with dressed hadrons

Helmut Haberzettl
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Abstract

Based on an effective field theory of hadrons in which quantum chromodynamics is assumed to provide the necessary bare cutoff functions, a gauge-invariant theory of pion photoproduction with fully dressed nucleons is described. The formalism provides consistent dynamical descriptions of pi-N --> pi-N scattering and Gamma-N --> pi-N production mechanisms in terms of nonlinear integral equations for fully dressed hadrons. The dressed hadron currents and the pion photoproduction current satisfy gauge invariance in a self-consistent manner. Approximations are discussed that make the nonlinear formalism manageable in practice and yet preserve gauge invariance.

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Helmut Haberzettl. 1997-09-24. Gauge-invariant theory of pion photoproduction with dressed hadrons. https://arxiv.org/abs/nucl-th/9709050

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