CP violation and FCNC in a warped A4 flavor model

We recently proposed a spontaneous A4 flavor symmetry breaking scheme implemented in a warped extra dimensional setup to explain the observed pattern of quark and lepton masses and mixings. The quark mixing is absent at leading order in the VEV expansion and it is induced at next-to-leading order by bulk A4 flavons mediating “crossbrane” interactions and a “cross-talk” between the quark and neutrino sectors. At this order, the possibility of producing hierarchical CKM entries, with all parameters of order one, stems from the presence of built-in cancellations induced by the hierarchical masses and the A4 flavor pattern. In this work we explore the phenomenology of RS-A4 and systematically obtain bounds on the Kaluza-Klein mass scale implied by flavor changing neutral current (FCNC) processes. In particular, we study the constraints arising from Re(ϵ′/ϵK), b → sγ, the neutron EDM and Higgs mediated FCNCs, while the tree level contribution to ϵK through a KK gluon exchange vanishes. We find an overall lower bound on the Kaluza-Klein massscale MKK ≳ 1.3 TeV from FCNCs, induced by b → sγ differently from flavor anarchic models. This bound is still weaker than the bound MKK ≳ 4.6 TeV induced by \( Z{b_L}{\bar{b}_L} \) in RS-A4. The little CP problem, related to the largely enhanced new physics contributions to the neutron EDM in flavor anarchic models, is absent. The subtleties of having the Higgs and flavons in the bulk are taken into account and final predictions are derived in the complete three-generation case.