A chiral quark model for meson electroproduction in the region of D-wave resonances
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The meson scattering and electroproduction amplitudes in the D13 , D33 and D15 partial waves are calculated in a coupled-channel formalism incorporating quasi-bound quark-model states, extending our previous studies of the P11 , P33 and S11 partial waves. The vertices of the baryon-meson interaction including the s - and d -wave pions and \( \rho\) -mesons, the s -wave \( \eta\) -meson, and the s - and p -wave \( \sigma\) -mesons are determined in the Cloudy Bag Model, with some changes of the parameters to reproduce the widths of the resonances. The helicity amplitudes and the electroproduction amplitudes exhibit consistent behavior in all channels but tend to be too weak compared to the experiment. We discuss possible origins of this discrepancy which arises also in the constituent quark model calculations.