A MODEL-INDEPENDENT DETERMINATION OF THE INCLUSIVE SEMILEPTONIC DECAY FRACTION OF B MESON

摘要

With the ARGUS detector at the e~+ e~- storage ring DORIS II, we have determined decay fraction and electron momentum spectrum of the inclusive decay mode B → ev X. Using lepton tags from the second B meson in 209000 γ(4S) → BB decays, we could determine the momentum spectrum for all momenta P_e > 0.6 GeV/c. Including the small extrapolation to P_e > 0, we find the model-independent decay fraction Br(B→ ev X) = (9.6 ± 0.5 ± 0.4)%. Adding D meson tags, our result is (9.7 ± 0.5 ± 0.4)%.