Final-state interaction and B→KK decays in perturbative QCD

We predict the branching ratios and CP asymmetries of the B→KK decays using the perturbative QCD factorization theorem, in which tree, penguin, and annihilation contributions, including both factorizable and nonfactorizable ones, are expressed as convolutions of hard six-quark amplitudes with universal meson wave functions. The unitarity angle φ₃=90° and the B and K meson wave functions extracted from experimental data of the B→Kπ and ππ decays are employed. Since the B→KK decays are sensitive to final-state interaction effects, the comparision of our predictions with future data can test the neglect of these effects in the above formalism. The CP asymmetry in the B^±→K^±K⁰ modes and the B_d⁰→K^±K^± branching ratios depend on annihilation and nonfactorizable amplitudes. The B→KK data can also verify the evaluation of these contributions.