Measurement of the Absolute Branching Fraction of D0 -> K- pi+

Abstract

We measure the absolute branching fraction for $D0\to K^{-}{\pi }^{+}$ using partial reconstruction of $B0bar\to D^{\ast +}X{\ell }^{-}{\bar{\nu }}_{\ell }$ decays. Only the charged lepton and the soft pion from the decay $D^{\ast +}\to D^0{\pi }^{+}$ are used. Based on a data sample of 230 million BBbar pairs collected at the ${\rm Y}(4S)$ resonance with the \babar detector at the PEP-II asymmetric-energy $B$ Factory at SLAC, we obtain ${\cal B}(\Dz \to \Km \pip) = (4.025 \pm 0.038 \pm 0.098)%$, where the first error is statistical and the second error is systematic.

arXiv commentLatex, 8 pages. Presented at Joint Meeting of Pacific Region Particle Physics Communities (DPF 2006 + JPS 2006), Honolulu, Hawaii, October 29 - November 03, 2006