Patterns of New Physics in B Decays

We show that any new physics (NP) which affects B decays with penguin contributions can be absorbed by redefinitions of the standard-model (SM) diagrammatic amplitudes. Hence, there are no clean signals of NP in such decays unless there is an accurate theoretical estimate of parameters or a justifiable approximation can be made. In all decays with penguin contributions, NP simultaneously affects pairs of diagrams. The evidence for a large C' from fits to B-> pi K data is naturally explained if NP contributes to P_EW, since NP affects the P_EW and C' diagrams as a pair. The weak phase gamma measured in B-> pi K decays will always agree with its SM value even in the presence of NP, if the NP contributes in such a way that the amplitudes retain the SM form after suitable redefinitions.