B[sub c]-Meson Decays and Lifetime within QCD Sum Rules.

On the basis of three-point sum rules, the form factors for the semileptonic decays B[sup +][sub c] → B[sub s](B[sup *][sub s])l[sup +]ν[sub l] are calculated with allowance for α[sub s]/υ Coulomb corrections for the heavy quarkonium. Generalized relations associated with spin symmetry within the approach combining heavy-quark effective theory and nonrelativistic QCD are derived for form factors in the region of recoil momenta close to zero. The nonleptonic decays of the B[sub c] meson are studied on the basis of the factorization hypothesis. By summing the main exclusive modes of c-quark decays and by using the results of a previous analysis of b-quark decays, the B[sub c]-meson lifetime is estimated within QCD sum rules and within nonrelativistic QCD. [ABSTRACT FROM AUTHOR]