The pole structure of low energy πN scattering amplitudes
Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China
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Published online: 1 February 2019
This report presents an investigation of the pion-nucleon elastic scattering in low energy region using a production representation of the partial wave S matrix. The phase shifts are separated into contributions from poles and branch cuts, where the left-hand cut term can be evaluated by tree-level covariant baryon chiral perturbation theory. A comparison between the sum of known contributions and the data in S- and P- wave channels is made. It is found that the known components in S11 and P11 channels are far from enough to saturate the corresponding experimental data, indicating the existence of low-lying hidden poles. The positions of those hidden poles are figured out and the physics behind them are explored.
© The Authors, published by EDP Sciences, 2019
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