Branching Fraction and Photon Energy Spectrum forb→sγ

We have measured the branching fraction and photon energy spectrum for the radiative penguin process $b\to s\gamma$. We find $B(b\to s\gamma )=(3.21\pm 0.43\pm {0.27}_{-0.10\mathrm{}}^{+0.18\mathrm{}})\times {10}^{-4\mathrm{}}$, 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, $〈E_{\gamma }〉=2.346\mathrm{}\pm 0.032\pm 0.011\mathrm{GeV}$, and $〈E_{\gamma }^2〉-〈E_{\gamma }{〉}^2=0.0226\mathrm{}\pm 0.0066\pm 0.0020{\mathrm{GeV}}^2$, where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order ${1/M}_B^3$ and ${\beta }_0{\alpha }_s^2$) the heavy quark effective theory parameter $\overline{\Lambda }=0.35\mathrm{}\pm 0.08\pm 0.10\mathrm{GeV}$.