TOWARDS THE CONTROL OVER ELECTROWEAK PENGUINS IN NONLEPTONIC B-DECAYS

We present strategies for determining electroweak penguins from experi mental data. Using the CKM-angle gamma as one of our central inputs an d making some reasonable approximations, we show that the (b) over bar --> (s) over bar electroweak penguin amplitude can be determined in a two-step procedure involving i) BR(B+ --> pi(0)K(+)), BR(B- --> pi(0) K(-)), BR(B+ --> pi(+)K(0)) and ii) either BR(B-d(0) --> pi(-)K(+)), B R(<(B)over bar(d)(0)> --> pi(+)K(-)) or a(CP)(t) of the mode B-s --> K +K-. The determination employing the B --> pi K transitions is not aff ected by SU(3)-breaking effects. Relating the (b) over bar --> (s) ove r bar electroweak penguin amplitude to the (b) over bar --> (d) over b ar case through SU(3) symmetry arguments, we are in a position to esti mate the electroweak penguin uncertainty affecting the extraction of t he CKM-angle alpha by using isospin relations among B --> pi pi decays . Our results allow in principle the determination of CKM-phases in a variety of B-decays.