Yukawa Hierarchies From Extra Dimensions With Small FCNC

Abstract

We investigate a class of extra dimensional models where all of the Standard Model fermions are localized to a single fixed point in an $S_1/Z_2$ orbifold, and each species is localized with an exponential wavefunction with a different width. We show that this naturally generates Yukawa hierarchies of the size present in the Standard Model, and we find a set of model parameters that reproduces the observed masses and mixings to experimental accuracy. In addition, the dominant constraints, arising from flavor changing neutral currents, are shown to restrict the compactification scale to be $1/R \ge 2-5 \tev$, which is a much less stringent constraint than in similar extra dimensional models of the Yukawa hierarchy.