Measurement of the Branching Fractions of Exclusive ¯¯¯B→D(*)(π)l−¯νl Decays in Events with a Fully Reconstructed B Meson

Abstract

We report a measurement of the branching fractions for ¯¯¯ B → D ( * ) ( π ) ℓ − ¯ ν ℓ decays based on 341.1 fb − 1 of data collected at the Υ ( 4 S ) resonance with the BABAR detector at the SLAC PEP-II e + e − storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We obtain B ( B − → D 0 ℓ − ¯ ν ℓ ) = ( 2.33 ± 0.09 stat ± 0.09 syst ) % , B ( B − → D * 0 ℓ − ¯ ν ℓ ) = ( 5.83 ± 0.15 stat ± 0.30 syst ) % , B ( ¯¯¯ B 0 → D + ℓ − ¯ ν ℓ ) = ( 2.21 ± 0.11 stat ± 0.12 syst ) % , B ( ¯¯¯ B 0 → D * + ℓ − ¯ ν ℓ ) = ( 5.49 ± 0.16 stat ± 0.25 syst ) % , B ( B − → D + π − ℓ − ¯ ν ℓ ) = ( 0.42 ± 0.06 stat ± 0.03 syst ) % , B ( B − → D * + π − ℓ − ¯ ν ℓ ) = ( 0.59 ± 0.05 stat ± 0.04 syst ) % , B ( ¯¯¯ B 0 → D 0 π + ℓ − ¯ ν ℓ ) = ( 0.43 ± 0.08 stat ± 0.03 syst ) % , and B ( ¯¯¯ B 0 → D * 0 π + ℓ − ¯ ν ℓ ) = ( 0.48 ± 0.08 stat ± 0.04 syst ) % .