Du, DS (reprint author), ACAD SINICA,INST HIGH ENERGY PHYS,POB 9184,BEIJING 100039,PEOPLES R CHINA.
We argue that the B-c exclusive nonleptonic decays are perturbatively calculable. Working in a perturbative QCD model of Brodsky et al, we pay attention to the estimate of the partial widths of the modes B-c --> J/Psi pi(+), J/Psi rho(+), etc., which serve to identify B-c mesons and determine the B-c mass and life time. Our estimations are found to be lower than the other predictions. We note that the spectator ansatz might be misleading in dealing with B-c weak decays. So the results will be potentially important at LHC to measure the B-c meson and to test various models of weak decays of heavy mesons.