The (Q7, Q1,2) contribution to (B)over-bar → Xsγ at O(αS2)

Interference between the photonic dipole operator Q(7) and the current-current operators Q(1,2) gives one of the most important QCD corrections to the (B) over bar -> X-s gamma decay rate. So far, the O(alpha(2)(s)) part of this correction has been known in the heavy charm quark limit only (m(c) >> m(b)/2). Here, we evaluate this part at m(c) = 0, and use both limits in an updated phenomenological study. Our prediction for the CP- and isospin-averaged branching ratio in the Standard Model reads B-s gamma(SM) = (3.36 +/- 0.23) x10(-4) for E-gamma > 1.6 GeV.