Waiting for the discovery of B_d⁰ → K ⁰K̄⁰

The CP asymmetries of the decay B_d⁰ → K ⁰ K̄⁰, which originates from b̄ → d̄ss̄ flavor-changing neutral-current processes, and its CP-averaged branching ratio BR(Bd → K⁰K̄⁰) offer interesting avenues to explore flavor physics. We show that we may characterize this channel, within the standard model, in a theoretically clean manner through a surface in observable space. In order to extract the relevant information from BR(B_d → K⁰ K̄⁰), further information is required, which is provided by the B → ππ system and the SU (3) flavor symmetry, where we include the leading factorizable SU (3)-breaking corrections and discuss how experimental insights into non-factorizable effects can be obtained. We point out that the standard model implies a lower bound for BR(B_d → K⁰K̄⁰), which is very close to its current experimental upper bound, thereby suggesting that this decay should soon be observed. Moreover, we explore the implications for "color suppression" in the B → ππ system, and convert the data for these modes in a peculiar standard-model pattern for the CP-violating B _d⁰ → K⁰K̄⁰ observables.