Final State Interaction In $B\to KK$ Decays

We study the final state interaction effects in $B\to KK$ decays. We find that the $t$ channel one-particle-exchange diagrams cannot enhance the branching ratios of $\overline{B^0}\to K^0\overline{K^0}$ and $B^{-}\to K^0{K}^{-}$ very sizably. For the pure annihilation process $\overline{B^0}\to K^{+}{K}^{-}$, the obtained branching ratio by final state interaction is at $\mathcal{O}({10}^{-8})$.