Measurement of $Br(D^0\to K^{-}{\pi }^{+})$ using Partila Reconstruction of $\bar{B}\to D^{\ast +}X{\ell }^{-}\bar{\nu }$

Abstract

We present a measurement of the absolute branching fraction for $D^0->K^{-}p{i}^{+}$ using the reconstruction of the decay chain $Bbar->D^{\ast +}X{l}^{-}nubar$, $D^{\ast +}->D^{0}p{i}^{+}$ where only the lepton and the low-momentum pion from the $D^{\ast +}$ are detected. With data collected by the CLEO II detector at the Cornell Electron Storage Ring, we have determined $Br(D^0->K^{-}p{i}^{+})=[3.81+-0.15(stat.)+-0.16(syst.)]$.

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