The two-particle decays of B_c^+ to psi pi^+(rho^+) and B_c^+ to eta_c pi^+(rho^+) are considered in a way taking into account a soft binding of quarks in the heavy quarkonia and a hard gluon exchange between the constituents at large recoil momenta of psi(eta_c). An approximate double enhancement of the amplitudes is found because of the nonspectator t-channel contribution.
@article{arxiv.hep-ph/9605451,
title = {Hard approximation in two-particle hadronic decays of B_c at large recoils},
author = {V. V. Kiselev},
journal= {arXiv preprint arXiv:hep-ph/9605451},
year = {2008}
}