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arXiv · 1503.01791

The (Q_7,Q_{1,2}) contribution to B -> X_s gamma at O(alpha_s^2)

Michal Czakon·Paul Fiedler·Tobias Huber·Mikolaj Misiak·Thomas Schutzmeier·Matthias Steinhauser
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Abstract

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 -> X_s gamma decay rate. So far, the O(alpha_s^2) 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^SM_{s gamma} = (3.36 +_ 0.23) * 10^-4 for E_gamma > 1.6 GeV.

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Michal Czakon, Paul Fiedler, Tobias Huber, Mikolaj Misiak, Thomas Schutzmeier, Matthias Steinhauser. 2015-03-05. The (Q_7,Q_{1,2}) contribution to B -> X_s gamma at O(alpha_s^2). https://arxiv.org/abs/1503.01791

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