Nucleon resonances with hidden charm in coupled-channels models

The model dependence of the predictions of nucleon resonances with hidden charm is investigated. We consider several coupled-channel models which are derived from relativistic quantum field theory by using (1) a unitary transformation method and (2) the three-dimensional reductions of the Bethe-Salpeter equation. With the same vector-meson exchange mechanism, we find that all models give very narrow molecularlike nucleon resonances with hidden charm in the mass range of 4.3 < M-R < 4.5 GeV, consistent with the previous predictions.