Complete ( O 7 , O 8 ) contribution to B̄ → X s γ at O ( α 2 s )

We calculate the set of O(αs) corrections to the branching ratio and to the photon energy spectrum of the decay process B̄ → Xsγ originating from the interference of diagrams involving the electromagnetic dipole operator O7 with diagrams involving the chromomagnetic dipole operator O8. The corrections evaluated here are one of the elements needed to complete the calculations of the B̄ → Xsγ branching ratio at next-to-next-to-leading order in QCD. We conclude that this set of corrections does not change the central value of the Standard Model prediction for Br(B̄ → Xsγ) by more than 1%.