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arXiv · 0906.2066

Pion electro-production in the Roper region in chiral quark models

B. Golli·S. Sirca·M. Fiolhais
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Abstract

We present a method to calculate pion electro-production amplitudes in a coupled-channel framework incorporating quasi-bound quark-model states. The method offers a clear prescription how to extract the resonant part of the amplitudes, even in the presence of different decay channels and a strong mixing of neighbouring resonances. The method is applied to the calculation of the M1- and the S1- amplitudes in the P11 partial wave in a simple chiral quark model. A good agreement with the observed M1- amplitude is found with a significant contribution from the pion cloud. The same effect is also prominent in the S1- amplitude but a rather uncertain data prevent us to draw a definitive conclusion.

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B. Golli, S. Sirca, M. Fiolhais. 2009-06-11. Pion electro-production in the Roper region in chiral quark models. https://doi.org/10.1140/epja/i2009-10878-2

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