TH - 626 hep - ph / 9905 XXX Factorization and Decay Constants

We calculate the decay constants of Ds and D∗ s with B̄0 → D+`−ν and B̄0 → D+D−(∗) s decays. In our analysis we take the factorization method with considering non-factorizable term contributions and used two different form factor behaviours (constant and monopoletype) for F0(q). We also consider the QCD-penguin and Electroweak-penguin contributions in hadronic decays within the NDR renormalization scheme at NLO calculation. We estimate the decay constant of the Ds meson to be 233 ± 49 MeV for (pole/pole)-type form factor and 255±54 MeV for (pole/constant)-type form factor. For D∗ s meson, we get fD∗ s = 346± 82 MeV, and fD∗ s /fDs = 1.43 ± 0.45 for (pole/constant)-type form factor. PACS index : 12.15.-y, 13.20.-v, 13.25.Hw, 14.40.Nd Keywards : Factorization, Non-leptonic Decays, Decay Constant, Penguin Effects ∗Email: [email protected] †Email: ccthmail.kek.jp; Monbusho Fellow in Japan