We evaluate in the framework of QCD factorization the two-loop vertex corrections to the decays
$$ {\overline{B}}_{(s)}\to {D}_{(s)}^{\left(\ast \right)+}{L}^{-} $$
and Λ
b
→ Λ
+
L
−, where L is a light meson from the set {π, ρ, K
(∗)
, a
1}. These decays are paradigms of the QCD factorization approach since only the colour-allowed tree amplitude contributes at leading power. Hence they are sensitive to the size of power corrections once their leading-power perturbative expansion is under control. He...
