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arXiv · 1012.5948

Spin observables in pion photoproduction from a unitary and causal effective field theory

A. M. Gasparyan·M. F. M. Lutz
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Abstract

Pion photoproduction is analyzed with the chiral Lagrangian. Partial-wave amplitudes are obtained by an analytic extrapolation of subthreshold reaction amplitudes computed in chiral perturbation theory, where the constraints set by electromagnetic-gauge invariance, causality and unitarity are used to stabilize the extrapolation. The experimental data set is reproduced up to energies $\sqrt{s}\simeq 1300$ MeV in terms of the parameters relevant at order $Q^3$. We present and discuss predictions for various spin observables.

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A. M. Gasparyan, M. F. M. Lutz. 2010-12-29. Spin observables in pion photoproduction from a unitary and causal effective field theory. https://arxiv.org/abs/1012.5948

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