Speaker
Description
Two-body non-leptonic $B$ decays with heavy-light final states, like $B_s \to D \pi$ and $B \to D K$, are among the theoretically cleanest non-leptonic decays as penguin loops do not contribute. They can be described using QCD factorization which relies on the heavy quark expansion. Advancing the theoretical calculations of such decays requires also a careful analysis of QED effects. In this talk we present a treatment of both virtual and ultrasoft real QED effects within a QCD $\times$ QED factorization framework of the non-leptonic and semi-leptonic $B$ to $D$ decays. In particular, due to recent discrepancies between theory and experimental data, we focus on ratios of non-leptonic over semi-leptonic decay rates, which are theoretically clean observables as the form factor dependence drops significantly. We found QED corrections to the amplitude to be at the sub-percent level, while at the level of the rate, ultrasoft photon effects can produce a correction up to a few percent, requiring a careful treatment of such effects in the experimental analyses.
