Unitarity Analyses of $\pi N$ Elastic Scattering Amplitudes

Abstract

The pion - nucleon scattering phase shifts in $s$ and $p$ waves are analyzed using PKU unitarization approach that can separate the phase shifts into different contributions from poles and branch cuts. It is found that in $S_{11}$ and $P_{11}$ channels, there exist large and positive missing contributions when one compares the phase shift from known resonances plus branch cuts with the experimental data, which indicates that those two channels may contain sizable effects from $N^{\ast }(1535)$ and $N^{\ast }(1440)$ shadow poles. Those results are obtained using tree level results of the $\pi N$ amplitude.

4 pages, 2 figures (the first figure contains 6 sub-figures), from proceedings of the 11th APCTP - BLTP JINR - PNPI NRC KI - SPbU Joint Workshop (held in Saint-Petersburg in July 23-28th)

References in corpus (7)

• Extended Partial-Wave Analysis of piN Scattering Data
• The chiral representation of the $\pi N$ scattering amplitude and the pion-nucleon sigma term
• Properties of baryon resonances from a multichannel partial wave analysis
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• Roy-Steiner equations for pion-nucleon scattering
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