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arXiv · 1712.09257

New Insights on Low Energy $πN$ Scattering Amplitudes

Yu-Fei Wang·De-Liang Yao·Han-Qing Zheng
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Abstract

The $S$- and $P$- wave phase shifts of low-energy pion-nucleon scatterings are analysed using Peking University representation, in which they are decomposed into various terms contributing either from poles or branch cuts. We estimate the left-hand cut contributions with the help of tree-level perturbative amplitudes derived in relativistic baryon chiral perturbation theory up to $\mathcal{O}(p^2)$. It is found that in $S_{11}$ and $P_{11}$ channels, contributions from known resonances and cuts are far from enough to saturate experimental phase shift data -- strongly indicating contributions from low lying poles undiscovered before, and we fully explore possible physics behind. On the other side, no serious disagreements are observed in the other channels.

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Yu-Fei Wang, De-Liang Yao, Han-Qing Zheng. 2018-03-28. New Insights on Low Energy $πN$ Scattering Amplitudes. https://doi.org/10.1140/epjc%2Fs10052-018-6024-5

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