Lifetime of theBcmeson and some relevant problems

The lifetime of the B-c meson is estimated by means of consistent considerations of all of the heavy mesons (B-0,B+/-,B-s,D-0,D',D-s) and the double heavy meson B-c itself as well. The framework, where the nonspectator effects for inclusive decays in terms of the optical theorem are taken into account properly, is adopted, and the parameters appearing in the estimate are treated phenomenologically by global fitting all the existing data for all the heavy mesons. In this estimation, special attention is paid to the masses of the heavy flavors and the bound-state effects as well. The present approach to the problem is meaningful because the numerical results show that the lifetime of the meson B-c can reach to the center value of the experimental observation. Because of the interference between the terms of the QCD correction from penguin diagrams and the main ones c(1)O(1), c(2)O(2), the total width of the meson B-c is enhanced by a factor about 3-4% that is different from the other heavy mesons and can be tested experimentally in the future.