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تسجيل مستخدم جديدDynamical Coupled-Channel Model of $pi N$ Scattering in the W $leq$ 2 GeV Nucleon Resonance Region
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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 $pipi N$ which has $piDelta$, $rho N$, 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. The parameters of the model are first determined by fitting as much as possible the empirical $pi N$ elastic scattering amplitudes of SAID up to 2 GeV. We then refine and confirm the resulting parameters by directly comparing the predicted differential cross section and target polarization asymmetry with the original data of the elastic $pi^{pm} p to pi^{pm} p$ and charge-exchange $pi^- p to pi^0 n$ processes. The predicted total cross sections of $pi N$ reactions and $pi Nto eta N$ reactions are also in good agreement with the data. Applications of the constructed model in analyzing the electromagnetic meson production data as well as the future developments are discussed.
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