Nonfactorizable contributions to B meson decays into charmonia

We analyze the B→(J/ψ,χc0,χc1,ηc)K(*) decays, which have small or even vanishing branching ratios in naive factorization assumption (FA). We calculate nonfactorizable corrections to FA in the perturbative QCD approach based on kT factorization theorem. The charmonium distribution amplitudes are inferred from the nonrelativistic heavy quarkonium wave functions. It is found that the nonfactorizable contributions enhance the branching ratios and generate the relative phases among helicity amplitudes of the above modes. Most of the observed branching ratios, polarization fractions, and relative phases, except those of B→ηcK, are explained. Our predictions for the B→(χc0,χc1,ηc)K* decays can be compared with future data.