Observation of B[over ¯]→D^{(*)} π^{+}π^{-}ℓ^{-}ν[over ¯] Decays in e^{+}e^{-} Collisions at the Υ(4S) Resonance.

PMID:26871322
Lees JP , Poireau V , Tisserand V , Grauges E , Palano A , Eigen G , Stugu B , Brown DN , Kerth LT , Kolomensky YG , Lee MJ , Lynch G , Koch H , Schroeder T , Hearty C , Mattison TS , McKenna JA , So RY , Khan A , Blinov VE , Buzykaev AR , Druzhinin VP ,
Physical review letters
We report on measurements of the decays of B[over ¯] mesons into the semileptonic final states B[over ¯]→D^{(*)}π^{+}π^{-}ℓ^{-}ν[over ¯], where D^{(*)} represents a D or D^{*} meson and ℓ^{-} is an electron or a muon. These measurements are based on 471×10^{6} BB[over ¯] pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R_{π^{+}π^{-}}^{(*)}=B(B[over ¯]→D^{(*)}π^{+}π^{-}ℓ^{-}ν[over ¯])/B(B[over ¯]→D^{(*)}ℓ^{-}ν[over ¯]) using events in which the second B meson is fully reconstructed. We find R_{π^{+}π^{-}}=0.067±0.010±0.008 and R_{π^{+}π^{-}}^{*}=0.019±0.005±0.004, where the first uncertainty is statistical and the second is systematic. Based on these results and assuming isospin invariance, we estimate that B[over ¯]→D^{(*)}ππℓ^{-}ν[over ¯] decays, where π denotes either a π^{±} and π^{0} meson, account for up to half the difference between the measured inclusive semileptonic branching fraction to charm hadrons and the corresponding sum of previously measured exclusive branching fractions.


Copyright(C) 2006 BIOIMPACT Co., Ltd. All Rights Reserved