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Measurement of the Branching Fraction of e^+e^- --> B0B0bar at the Upsilon(4S) Resonance

The BABAR Collaboration·B. Aubert
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Abstract

We report a measurement of the branching fraction e^+e^- --> B0B0bar with a data sample of 81.7 fb^-1 collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy e^+e^- storage ring. Using partial reconstruction of the decay B0bar --> D^{*+} \ell^{-} \barν_{\ell} we obtain a preliminary result of f00 = 0.486 +- 0.010(stat.) +- 0.009(sys.). Our result does not depend on branching fractions of the B0bar and the D^{*+} decay chains, on the simulated reconstruction efficiency, on the ratio of the charged and neutral B meson lifetimes, nor on assumption of isospin symmetry. This measurement is important for normalizing many B decay branching fractions, and contributes to our understanding of isospin violation in the Upsilon(4S) system.

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The BABAR Collaboration, B. Aubert. 2004-08-10. Measurement of the Branching Fraction of e^+e^- --> B0B0bar at the Upsilon(4S) Resonance. https://arxiv.org/abs/hep-ex/0408022

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