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arXiv · 1610.01017

Empirical parametrizations of the resonance amplitudes based on the Siegert's theorem

G. Ramalho
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Abstract

We present parametrizations of the $γ^\ast N \to N(1535)1/2^-$, $γ^\ast N \to N(1520)3/2^-$ and $γ^\ast N \to Δ(1232)3/2^+$ transition amplitudes that are compatible with the analytic constraints at the pseudothreshold (Siegert's theorem). The presented parametrizations also provide a fair description of the experimental data. For the case of the $γ^\ast N \to Δ(1232)3/2^+$ transition, we discuss how the pion cloud parametrizations of the electric and the Coulomb quadrupole form factors can be adjusted according to the Siegert's theorem.

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G. Ramalho. 2016-10-03. Empirical parametrizations of the resonance amplitudes based on the Siegert's theorem. https://doi.org/10.7566/jpscp.13.020039

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