Failure of the commonly used B -> K(K^*) form factors in explaining   recent data on B -> J/\Psi + K ( K^* ) decays
  We establish restrictions on $B \ra K ( K^* )$ form factors imposed by recent data on $B \ra J/\Psi + K ( K^* ) $ decay rates and polarization. We show that these constraints are not satisfied by few commonly used models. Finally, we relate $B \ra K ( K^* )$ form factors to those in $D \ra K ( K^* )$ transitions using the heavy flavour symmetry as proposed by Isgur and Wise and discuss the uncertainties in this procedure. We find that this method also leads to form factors excluded by data. 
M. Gourdin, A. N. Kamal and X. Y. Pham