Implications of the Fleischer-Mannel bound Original Research Article

Fleischer and Mannel (FM) have shown that it may become possible to constrain the angle γ of the unitarity triangle from measurements of various B → πK decays. This constraint is independent of hadronic uncertainties to the few percent level. We show that, within the Standard Model, the FM bound can give strong constraints on the CKM parameters. In particular, it could predict a well-defined sign for sin 2γ and sin 2α. In a class of extensions of the Standard Model, where New Physics affects only ΔB = 2 (and, in particular, not ΔB = 1) processes, the FM bound can lead to constraints on CP asymmetries in B decays into final CP eigenstates even if B − B− mixing is dominated by unknown New Physics. In our analysis, we use a new method to combine in a statistically meaningful way the various measurements that involve CKM parameters.