engleski

Singularity structure of the PiN scattering amplitude in a meson-exchange model up to energies W < 2.0 GeV

Within the previously developed Dubna-Mainz-Taipei meson-exchange model, the singularity structure of the ¼N scattering amplitudes has been investigated. For all partial waves up to F waves and c.m. energies up to W ~ 2 GeV, the T-matrix poles have been calculated by three different techniques: analytic continuation into the complex energy plane, speed-plot, and regularization method. For all 4-star resonances except the S11(1535), we find very good agreement between the analytic continuation and the regularization method. We also find resonance poles for resonances that are not so well established, but in these cases the pole positions and residues obtained by analytic continuation can substantially differ from the results predicted by the speed-plot and regularization methods.

pion-nucleon interaction ; baryon resonances ; T-matrix poles ; speed plot ; regularization method

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