Calculation of the D- and B-meson lifetimes and the unitarity triangle parameters

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-+/-,D-0,D-s decay widths and the B-+/-,B-0,B-s lifetime differences and branching ratios. The results for D-mesons are in reasonable agreement with the data, while it is predicted that [Gamma(B-d) - Gamma(B-)]/Gamma(B) similar or equal to 4%, and the lifetime difference of the B-d and B-s mesons is even smaller. The lifetime difference of the long- and short-lived B-s mesons is predicted to be: [Gamma(B-s(short)) - Gamma(B-s(long))]/<(Gamma)over bar>(B-s) similar or equal to 8%, the mass difference ratio of the short- and long-lived B-s and B-d mesons is: Delta m(s)/Delta m(d) similar or equal to 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: M(c) similar or equal to 1.65 GeV, M(b) similar or equal to 5.04 GeV, and the decay constants are: f(D)(M(c)) similar or equal to 165 MeV, f(B)(M(b)) similar or equal to 120 MeV. It is also shown that the nonfactorizable corrections to the B-0 - (B) over bar(0) mixing are large and, in particular, the (b)d meson ''bag factor'' is: B-B(M(b)) similar or equal to (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 epsilon'/epsilon which is too large): lambda similar or equal to 0.221, A similar or equal to 0.86. rho similar or equal to -0.36, eta similar or equal to 0.19.