How hard are the form factors in hadronic vertices with heavy mesons?

The ND Lambda (c) and ND*Lambda (c), form factors are evaluated in a full Q CD sum rule calculation. We study the double Borel sum rule for the three p oint function of one meson one nucleon and one Lambda (c) current up to ord er six in the operator product expansion. The double Borel transform is per formed with respect to the nucleon and Lambda (c) momenta, and the form fac tor is evaluated as a function of the momentum Q(2) of the heavy meson. The se form factors are relevant to evaluate the charmonium absorption cross se ction by hadrons. Our results are compatible with constant form factors in these vertices. (C) 2001 Published by Elsevier Science B.V.