New aspects of B → ππ, πK and their implications for rare decays
Physik Department, Technische Universität München, 85748, Garching, Germany
2 Theory Division, Department of Physics, CERN, 1211 Geneva 23, Switzerland
3 Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805, Munich, Germany
Published online: 24 January 2006
We analyze the B → ππ, πK modes in the light of the most recent B-factory data, and obtain the following new results: (i) the modes prefer γ = (74±6)°, which - together with |V ub /V cb | - allows us to determine the "true" unitarity triangle and to search for CP-violating new-physics contributions to B 0 d - mixing; (ii) the B → πK puzzle reflected in particular by the low experimental value of the ratio R n of the neutral B → πK rates persists and still favors new physics in the electroweak penguin sector with a new CP-violating phase ϕ ~ –90°, although now also ϕ ~ +90° can bring us rather close to the data; (iii) the mixing-induced CP asymmetry is a sensitive probe of the sign of this phase, and would currently favor ϕ ~ +90°, as well as the direct CP asymmetry of , which suffers, however, from large hadronic uncertainties; (iv) we investigate the sensitivity of our B → πK analysis to large non-factorizable SU(3)-breaking effects and find that their impact is surprisingly small so that it is indeed exciting to speculate on new physics; (v) assuming that new physics enters through Z 0 penguins, we study the interplay between B → πK and rare B, K decays and point out that the most recent B-factory constraints for the latter have interesting implications, bringing us to a few scenarios for the future evolution of the data, where also the mixing-induced CP violation in plays a prominent rôle.
© Springer-Verlag, 2006