Spin effects in B_c -> X_cc + \pi (\rho) decays
  The two-particle hadronic decays of B_c meson into S-wave and P-wave charmonium states X_cc are considered in the framework of hard gluon exchange model. It is shown that decay width of B_c meson into S-wave charmonium states doubly exceeds one for S-wave states. In compare with the previous estimations we predict the enhancement by 8 % the branching ratio for the B_c decays into J/psi in the two-particle hadronic decays via the contribution of the radiative decays of P-wave states in the cascade processes. 
V.A.Saleev