Determination of /Vcb/ from the semileptonic decay B0 → D*-ℓ+ν

Semileptonic decays B→ D*-ℓ+νX were selected from a sample of 3.1 million hadronic Z decays collected by the DELPHI detector at LEP. A topological search for semileptonic B decays to resonant and non-resonant D*-π+ states was performed and the ratio of the branching fractions: Br(B → D*-ℓ+νX)/Br(B → D*-+νX) + Br(B0 → + D*-ℓ+ν) = 0.19 ± 0.10(stat) ± 0.06(syst) was determined. Taking into account this contribution, the differential decay width of B0 → D*-ℓ+ν was measured as a function of the momentum transfer from the B to the D*- in two separate analyses, using exclusive and inclusive methods of D*- reconstruction. The distributions were fitted over the full momentum transfer range to extract the product of {pipe}Vcb{pipe} times the normalization of the decay form factor F(q2max): F(q2max){pipe}Vcb{pipe} = (35.4 ± 1.9(stat) ± 2.4(syst)) · 10-3. The value of {pipe}Vcb{pipe} was computed using theoretical calculations of F(q2max), giving: {pipe}Vcb{pipe} = (38.9 ± 2.0(stat) ± 2.6(syst) ± 1.7(theory)) · 10-3. The total branching fraction Br(B0 → D*-ℓ+ν) was determined to be: Br(130, D*-ℓ+v) = (5.52 ± 0.17(stat) ± 0.68(syst))%. © Springer-Verlag 1996.0SCOPUS: ar.j