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Determination of the Branching Fraction for Inclusive Decays B -> X_{s} gamma

B. Aubert·BaBar Collaboration
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Abstract

We present a preliminary determination of the inclusive branching fraction for the rare radiative penguin transition B -> X_{s} gamma. The measurement is based on a data sample of 60 million BB pairs collected between 1999 and 2001 with the BaBar detector at the PEPII asymmetric-energy e+e- B Factory at SLAC. We study events containing a high-energy photon from one B (or Bbar) decay and a tagging primary lepton from the decay of the other B meson. By this means, we are able to reduce a significant component of the background without introduction of model dependent uncertainties in the event selection efficiency. We determine the branching fraction BR(B->X_{s} gamma)=3.88 +-0.36(stat.)+-0.37(sys.) +0.43-0.23(model.)x10^{-4}, which is consistent with Standard Model predictions and provides a constraint on possible new physics contributions to the electromagnetic penguin amplitude in B decays.

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B. Aubert, BaBar Collaboration. 2002-07-25. Determination of the Branching Fraction for Inclusive Decays B -> X_{s} gamma. https://arxiv.org/abs/hep-ex/0207076

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