Abstract :
Using the expansions of the heavy-meson decay widths in the heavy quark mass and QCD sum rules for estimates of the corresponding matrix elements, we calculate the D±,0,s decay widths and the B±,0,s lifetime differences and branching ratios. The results for D-mesons are in reasonable agreement with the data, while it is predicted that [г (Bd) - г (B−)]/гB ≅ 4%, and the lifetime difference of the Bd and Bs mesons is even smaller. The lifetime difference of the long- and short-lived Bs mesons is predicted to be: [г (Bshorts) - г (Blongs)]/г(Bs ≅ 8%, the mass difference ratio of the short- and long-lived Bs and Bd mesons is: Δms/Δmd ≅ 14, etc. The role of the weak annihilation and Pauli interference contributions to the lifetime differences are described in detail. In the course of self-consistent calculations the values of many parameters crucial for calculations with charmed and beauty mesons are found. In particular, the quark pole masses are: Mc ≅ 1.65 GeV, Mb ~- 5.04 GeV, and the decay constants are: ƒD (Mc) ≅ 165 MeV, ƒB(Mb) ≅ 120 MeV It is also shown that the nonfactorizable corrections to the B0 - B⊂ mixing are large and, in particular, the Bd meson “bag factor” is: BB (Mb) ≅ (1–18%). The values of the unitarity triangle parameters are found, which are consistent with these results and the data available (except for the NA31 result for the ϵ′/ϵ which is too large): λ ≅ 0.221, A ≅ 0.86. ρ≅−0.36, η≅0.19.
