Abstract
We present a model for the γ*N → N* helicity amplitudes, where N is the nucleon and N* is a negative parity nucleon excitation, member of the SU(6)-multiplet [70, 1-]. The model combines the results from the single quark transition model for the helicity amplitudes with the results of the covariant spectator quark model for the γ*N → N* (1535) and γ*N → N* (1520) transitions. With the knowledge of the amplitudes A1/2 and A3/2 for those transitions we calculate three independent coefficients defined by the single quark transition model and make predictions for the helicity amplitudes associated with the γ*N → N* (1650), γ*N → N* (1700), γ*N → Δ (1620), and γ*N → Δ (1700) transitions. In order to facilitate the comparison with future experimental data at high Q2, we provide also simple parametrizations for the amplitudes, compatible with the expected falloff at high Q2.
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