QCD factorization in B → πK, ππ decays and extraction of Wolfenstein parameters

In the heavy-quark limit, the hadronic matrix elements entering nonleptonic B-meson decays into two light mesons can be calculated from first principles including "nonfactorizable" strong-interaction corrections. The B --> piK, pi pi decay amplitudes are computed including electroweak penguin contributions, SU(3) violation in the light-cone distribution amplitudes, and an estimate of power corrections from chirally-enhanced terms and annihilation graphs. The results are then used to reduce the theoretical uncertainties in determinations of the weak phases gamma and alpha. In that way, new constraints in the (<(<rho>)over bar>, <(<eta>)over bar>) plane are derived. Predictions for the B --> nK, pi pi branching ratios and CP asymmetries are also presented. A good global fit to the (in part preliminary) experimental data on the branching fractions is obtained without taking recourse to phenomenological models. (C) 2001 Elsevier Science B.V. All rights reserved.