Update of the nonlocal sub-leading ${O}_1$-${O}_7$ contribution to $\bar B \to X_s \gamma$ at LO

Abstract

In all previous calculations of the non-local sub-leading contribution to the inclusive penguin decay $\bar B \to X_s \gamma$ due to the interference of the electroweak operators ${O}_1^c$ - ${O}_{7\gamma}$ the local Voloshin term was subtracted. In view of the ongoing analysis at order $\alpha_s$, we present a calculation of the complete non-local contribution which takes into account the high correlation between the uncertainties of the local Voloshin and the non-local term of the previous analyses. The new calculation has a high impact on the range of the non-local contribution.