Penguin Amplitudes in Hadronic B Decays: Nlo Spectator Scattering

We present results on the NLO (α2s) spectator-scattering corrections to the topological penguin amplitudes for charmless hadronic two-body B-decays in QCD factorization. The corrections can be sizable for the colour-suppressed electroweak penguin amplitudes α 4,EW but otherwise are numerically small. Our results explicitly demonstrate factorization at this order. To assess the phenomenological viability of the framework, we consider penguin-to-tree ratios in the penguindominated πK system and find agreement to the expected precision (i.e., a power correction).