Charming penguins strike back

By using the recent experimental measurements of B --> pi pi and B --> K pi branching ratios, we find that factorization is unable to reproduce the ob served BRs even taking into account the uncertainties of the input paramete rs. Charming and GIM penguins allow to reconcile the theoretical prediction s with the data. Because of these large effects, we conclude, however, that it is not possible, with the present theoretical and experimental accuracy , to determine the CP violation angle gamma from these decays. Contrary to factorization, we predict large asymmetries for several of the particle-ant iparticle BRs, in particular BR(B+ --> K(+)pi (0)), BR(B-d --> K(+)pi (-)) and BR(B-d --> pi (+)pi (-)). This opens new perspectives for the study of CP violation in B systems. (C) 2001 Elsevier Science B.V. All rights reserv ed.