Measurement of the Branching Fractions of ¯¯¯B→D**ℓ−¯νℓ Decays in Events Tagged by a Fully Reconstructed B Meson

Abstract

We report a measurement of the branching fractions of ¯¯¯ B → D ** ℓ − ¯ ν ℓ decays based on 417 fb − 1 of data collected at the Υ ( 4 S ) resonance with the BABAR detector at the PEP-II e + e − storage rings. Events are selected by fully reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m ( D ( * ) π ) − m ( D ( * ) ) is performed to extract the signal yields of the different D ** states. We observe the ¯¯¯ B → D ** ℓ − ¯ ν ℓ decay modes corresponding to the four D ** states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties.