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Pion photoproduction on the nucleon in the quark model

2002; American Institute of Physics; Volume: 65; Issue: 6 Linguagem: Inglês

10.1103/physrevc.65.065204

1538-4497

Q. Zhao, Jim Al-Khalili, Z.-P. Li, R. L. Workman,

High-Energy Particle Collisions Research

We present a detailed quark-model study of pion photoproduction within the effective Lagrangian approach. Cross sections and single-polarization observables are investigated for the four charge channels, $\gamma p\to \pi^+ n$, $\gamma n\to \pi^- p$, $\gamma p\to \pi^0 p$, and $\gamma n\to \pi^0 n$. Leaving the $\pi N\Delta$ coupling strength to be a free parameter, we obtain a reasonably consistent description of these four channels from threshold to the first resonance region. Within this effective Lagrangian approach, strongly constrainted by the quark model, we consider the issue of double-counting which may occur if additional {\it t}-channel contributions are included.