Branching Fraction and Photon Energy Spectrum b -> s gamma
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, < Eγ > = 2.346 +- 0.032 +- 0.011 GeV, and <E2gamma> - <Egamma>2 = 0.0226 +- 0.0066 +- 0.0020 GeV2, where the errors are statistical and systematic. From the first moment we obtain (in MS[Bar], to order 1/M3 and beta0 alphas2) the HQET parameter Lambda[Bar] = 0.35 +- 0.08 +- 0.10 GeV.
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