Model-independent electroweak penguin amplitudes in B decays to two pseudoscalars - art. no. 034021.

We study the effects of electroweak penguin (EWP) amplitudes in B meson dec ays into two charmless pseudoscalars in the approximation of retaining only the dominant EWP operators Q(9) and Q(10). using flavor SU(3) symmetry, we derive a set of model-independent relations between EWP contributions and tree-level decay amplitudes one of which was noted recently by Neubert and Rosner. Two new applications of these relations are demonstrated in which u ncertainties due to EWP corrections are eliminated in order to determine a weak phase. Whereas the weak angle alpha can be obtained from B --> pi pi f ree of hadronic uncertainties, a determination of gamma from B-0,B-+/- --> K pi(+/-) requires the knowledge of a ratio of certain tree-level hadronic matrix elements. The smallness of this ratio implies a useful constraint on gamma if rescattering can be neglected. [S0556-2821(99)01815-9].