Flavor structure of warped extra dimension models

Abstract

We recently showed that warped extra-dimensional models with bulk custodial symmetry and few TeV Kaluza-Klein (KK) masses lead to striking signals at $B$ factories. In this paper, using a spurion analysis, we systematically study the flavor structure of models that belong to the above class. In particular we find that the profiles of the zero modes, which are similar in all these models, essentially control the underlying flavor structure. This implies that our results are robust and model independent in this class of models. We discuss in detail the origin of the signals in $B$ physics. We also briefly study other new physics signatures that arise in rare $K$ decays ($K\to \pi \nu \nu$), in rare top decays [$t\to c\gamma (Z,\mathrm{\text{gluon}})$], and the possibility of $CP$ asymmetries in $D^0$ decays to $CP$ eigenstates such as $K_S{\pi }^0$ and others. Finally we demonstrate that with light KK masses, $\sim 3\mathrm{T}\mathrm{e}\mathrm{V}$, the above class of models with anarchic 5D Yukawas has a “$CP$ problem” since contributions to the neutron electric dipole moment are roughly 20 times larger than the current experimental bound. Using $\mathrm{A}\mathrm{d}\mathrm{S}/\mathrm{C}\mathrm{F}\mathrm{T}$ correspondence, these extra-dimensional models are dual to a purely 4D strongly coupled conformal Higgs sector thus enhancing their appeal.