ELECTROWEAK PENGUIN DIAGRAMS AND 2-BODY B-DECAYS

We discuss the role of electroweak penguin diagrams in B decays to two light pseudoscalar mesons. We confirm that the extraction of the weak phase alpha through the isospin analysis involving B --> pi pi decays is largely unaffected by such operators. However, the methods proposed to obtain weak and strong phases by relating B --> pi pi, B --> pi K, and B --> K (K) over bar decays through flavor SU(3) will be invalidated if electroweak penguin diagrams are large. We show that, although the introduction of electroweak penguin contributions introduces no new amplitudes of flavor SU(3), there are a number of ways to experimentally measure I he size of such effects. Finally, using SU(3) amplitude relations we present a new way of measuring the weak angle gamma which holds even in the presence of electroweak penguin diagrams.