Strong Couplings of Three Mesons with Charm(ing) Involvement
  We determine the strong couplings of three mesons that involve, at least, one $\eta_c$ or $J/\psi$ meson, within the framework of a constituent-quark model by means of relativistic dispersion formulations. For strong couplings of $J/\psi$ mesons to two charmed mesons, our approach leads to predictions roughly twice as large as those arising from QCD sum rules. 
Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian, Silvano Simula
hep-ph nucl-th