Dynamical Coupled-Channel Model of $\pi N$ Scattering in the W $\leq$ 2 GeV Nucleon Resonance Region

Understand

As a first step to analyze the electromagnetic meson production reactions in the nucleon resonance region, the parameters of the hadronic interactions of a dynamical coupled-channel model, developed in {\it Physics Reports 439, 193 (2007)}, are determined by fitting the $\pi N$ scattering data.

• The channels included in the calculations are $\pi N$, $\eta N$ and $\pi\pi N$ which has $\pi\Delta$, $\rho N$, and $\sigma N$ resonant components.
• The non-resonant meson-baryon interactions of the model are derived from a set of Lagrangians by using a unitary transformation method.
• One or two bare excited nucleon states in each of $S$, $P$, $D$, and $F$ partial waves are included to generate the resonant amplitudes in the fits.