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

TL;DR

This paper reports a precise measurement of the absolute branching fraction of D0 decaying into K- pi+ using partial reconstruction techniques on a large data sample from the BaBar experiment.

Contribution

It introduces a novel partial reconstruction method to measure the D0 decay branching fraction with high precision, utilizing data from the BaBar detector.

Findings

Measured ${ m BF}(D^0 o K^- o ar{ u}_{ ext{l}})$ as (4.025 ± 0.038 (stat) ± 0.098 (syst))%.

Achieved a significant reduction in systematic uncertainties compared to previous measurements.

Demonstrated the effectiveness of partial reconstruction in charm meson decay studies.

Abstract

We measure the absolute branching fraction for $D0 \to K^{-} \pi^{+}$ using partial reconstruction of $B0bar \to D^{*+} X \ell^{-} \bar{\nu}_{\ell}$ decays. Only the charged lepton and the soft pion from the decay $D^{*+} \to D^{0} \pi^{+}$ are used. Based on a data sample of 230 million BBbar pairs collected at the $\Upsilon(4S)$ 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.