Update of the Standard-Model prediction for $\bar B \to X_s γ$

Abstract: We report on two recent calculations on the inclusive radiative decay $\bar B\to X_s γ$, notably multi-parton contributions at NLO and the $Q_{1,2}-Q_7$ interference at NNLO for the physical value of the charm-quark mass. The former calculation formally completes $\bar{B} \rightarrow X_s γ$ at NLO in QCD at leading power, the latter removes a long-standing $\pm 3\%$ uncertainty arising from interpolation in $m_c$. The updated Standard-Model prediction for the CP- and isospin-averaged branching ratio reads $${\mathcal B}<em>{s γ}^{\rm SM} = (3.54 \pm 0.14)\times 10<sup>{-4}$$ for photon energies $E</em>γ&gt; 1.6\,{\rm GeV}$ in the $B$-meson rest frame. This value is in good agreement with the current experimental average $${\mathcal B}_{s γ}^{\rm exp} = (3.49 \pm 0.19)\times 10<sup>{-4}$$.