Dynamical coupled channel calculation of pion and omega meson production
  A dynamical coupled channel approach is used to study $\pi$ and $\omega$--meson production induced by pions and photons scattering from the proton. Six intermediate channels including $\pi N$, $\eta N$, $\pi\Delta$, $\sigma N$, $\rho N$ and $\omega N$ are employed to describe unpolarized and polarized data. Bare parameters in an effective hadronic Lagrangian are determined in a fit to data for $\pi N \to \pi N$, $\gamma N \to \pi N$, $\pi^- p \to \omega n$, and $\gamma p \to \omega p$ reactions at center-of-mass energies from threshold to $W < 2.0$ GeV. The $T$ matrix determined in these fits is used to calculate the photon beam asymmetry for $\omega$-meson production and the $\omega N \to\omega N$ total cross section and $\omega N$ scattering lengths. 
Mark W. Paris