Analysis of γ Determinations from B → πK Decays Andrzej

We present a general parametrization of B → πK, π0K± and Bd → π0K, πK decays, taking into account both electroweak penguin and rescattering effects. This formalism allows – among other things – an improved implementation of the strategies that were recently proposed by Neubert and Rosner to probe the CKM angle γ with the help of B → πK, π0K± decays. In particular, it allows us to investigate the sensitivity of the extracted value of γ to the basic assumptions of their approach. We find that certain SU(3)-breaking effects may have an important impact and emphasize that additional hadronic uncertainties are due to rescattering processes. The latter can be controlled by using SU(3) flavour symmetry arguments and additional experimental information provided by B → KK modes. We propose a new strategy to probe the angle γ with the help of the neutral decays Bd → π0K, πK, which is theoretically cleaner than the B → πK, π0K± approach. Here rescattering processes can be taken into account by just measuring the CP-violating observables of the decay Bd → πKS. Finally, we point out that an experimental analysis of Bs → K+K− modes would also be very useful to probe the CKM angle γ, as well as electroweak penguins, and we critically compare the virtues and weaknesses of the various approaches discussed in this paper. As a by-product, we point out a strategy to include the electroweak penguins in the determination of the CKM angle α from B → ππ decays. CERN-TH/98-319 October 1998