Form factor relations for heavy-to-heavy and heavy-to-light meson   transitions
  Relations between the form factors that parametrize the hadronic matrix elements, in spectator decays of heavy mesons, have been derived by Stech within the constituent quark model. In here, we examine these relations using a slightly modified description of the meson states. We find new and very general relations for some of the form factors. For the other form factors, we obtain small modifications to the relations previously derived by Stech, in the case of heavy-to-light transitions. 
Joao M. Soares