TTP06-26 The first estimate of Bbar -> Xs gamma at O(alpha_s^2)

Xs gamma at O(alpha_s^2) > Combining our results for various ${\cal O}(\alpha_s^2)$ corrections

 to
 the weak radiative $B$-meson decay, we are able to present the first
 estimate of the branching ratio at the next-to-next-to-leading order
 in QCD.
 We find ${\cal B}({\bar B}\to X_s\gamma) = (3.15 \pm 0.23) \times
 10^{-4}$
 for $E_{\gamma} > 1.6\;$GeV in the ${\bar B}$-meson rest frame. The
 four
 types of uncertainties: non-perturbative (5\%), parametric (3\%),
 higher-order (3\%) and $m_c$-interpolation ambiguity (3\%) have been
 added in quadrature to obtain the total error.