Bc decays and lifetime in QCD sum rules

In the framework of three-point QCD sum rules, the form factors for the semileptonic decays of Bc+→Bs(Bs*)l+νl are calculated with account for the Coulomb-like αs/v -corrections in the heavy quarkonium. The generalized relations due to the spin symmetry of HQET / NRQCD for the form factors are derived at the recoil momentum close to zero. The nonleptonic decays are studied using the assumption on the factorization. The Bc -meson lifetime is estimated by summing up the dominating exclusive modes in the c→s transition combining the current calculations with the previous analysis of b→c decays in the sum rules of QCD and NRQCD