We analyze the $\gamma N\to\pi N$ process in the negative parity channel with Hamiltonian effective filed theory which is successful in studying the nucleon resonances associated with the meson-nucleon scattering and lattice QCD simulations. We provide the scattering amplitude of pion photoproduction and extract the electric dipole amplitudes $E_{ 0+}$. The triquark component in $N^*(1535)$ is important for improving the consistence between our results and the experimental data.
Categories: hep-ph nucl-th