The controversy about "1/m_Q duality violation" ; a quark model point of   view
  A detailed discussion based on exact calculations, possible in the non relativistic quark model, is given to show that there is no 1/m_Q term in the heavy quark expansion of totally integrated semileptonic decay rates. More generally, it is shown that OPE holds with very few terms in the expansion, at least in the harmonic oscillator model. 
Alain Le Yaouanc, Dimitri Melikhov, Vincent Morenas, Lluis Oliver,   Olivier Pene, Jean-Claude Raynal