Hadronic rare B decays via exchange or annihilation diagrams

The two-body mesonic B decays induced only via a single W-exchange or annihilation quark diagram, such as B-u(-) --> D-s((*)-) K((*)0) and (B) over bar(d)(0) --> D-s((*)+) K-(*-), are analyzed in the factorization approximation. We estimate the branching ratios for those transitions into two pseudoscalar mesons, and find them to be negligibly small. The significant effect of final-state rescattering is illustrated by taking B-u(-) --> D-(K) over bar(0), for example.