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Branching Fraction and Photon Energy Spectrum b -> s gamma

S. Chen·CLEO Collaboration
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Abstract

We have measured the branching fraction and photon energy spectrum for the radiative penguin process b -> s gamma. We find BR(b -> s gamma) = (3.21 +- 0.43 +- 0.27 +0.18 -0.10) 10^(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, < E_γ> = 2.346 +- 0.032 +- 0.011 GeV, and - ^2 = 0.0226 +- 0.0066 +- 0.0020 GeV^2, where the errors are statistical and systematic. From the first moment we obtain (in MS[Bar], to order 1/M^3 and beta_0 alpha_s^2) the HQET parameter Lambda[Bar] = 0.35 +- 0.08 +- 0.10 GeV.

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S. Chen, CLEO Collaboration. 2001-10-25. Branching Fraction and Photon Energy Spectrum b -> s gamma. https://doi.org/10.1103/physrevlett.87.251807

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