Penguins, trees and final state interactions in B decays to flavor mixed mesons

Final state interactions are the catch-22 in planning CP violation experiments using B decays. If FSI are unknown and appreciable, calculations of contributions of various weak interaction diagrams are unreliable. But if FSI are negligible, the contributions from tree and penguin diagrams have the same strong phase and cannot produce a CP-violating charge asymmetry. We show how analysis of certain related decays can pinpoint and clarify the role of FSI. We focus on decays into flavor-mixed neutral nonstrange mesons which are particularly sensitive via interference to small contributions from secondary diagrams, immune to various symmetry-breaking diseases and may avoid the catch-22 via the OZI rule.