Four-point functions and kaon decays in a minimal AdS/QCD model

We study the predictions of holographic QCD for various observable four-point quark-flavor current-current correlators. The dual 5-dimensional bulk theory we consider is a SU(3)(L) x SU(3)(R) Yang-Mills theory in a slice of AdS(5) spacetime with boundaries. Particular UV and IR boundary conditions encode the spontaneous breaking of the dual 4D global chiral symmetry down to the SU(3)(V) subgroup. We explain in detail how to calculate the 4D four-point quark-flavor current-current correlators using the 5D holographic theory, including interactions. We use these results to investigate predictions of holographic QCD for the Delta I = 1/2 rule for kaon decays and the B-K parameter. The results agree well in comparison with experimental data, with an accuracy of 25% or better. The holographic theory automatically includes the contributions of the meson resonances to the four-point correlators. The correlators agree well in the low-momentum and high-momentum limit, in comparison with chiral perturbation theory and perturbative QCD results, respectively.