An A4 flavor model for quarks and leptons in warped geometry

TL;DR

This paper introduces a warped extra-dimensional A4 flavor symmetry model that naturally explains fermion mass hierarchies, neutrino mixing, and quark mixing patterns while suppressing flavor violations.

Contribution

It presents a novel A4 flavor symmetry breaking scheme in warped geometry that accounts for fermion masses, mixings, and CP violation with minimal assumptions and improved flavor violation suppression.

Findings

Explains fermion mass hierarchies via wave function overlaps.

Achieves tribimaximal neutrino mixing and zero quark mixing at leading order.

Provides a natural explanation for the CKM matrix and CP phase.

Abstract

We propose 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 main advantages of this choice are the explanation of fermion mass hierarchies by wave function overlaps, the emergence of tribimaximal neutrino mixing and zero quark mixing at the leading order and the absence of tree-level gauge mediated flavor violations. Quark mixing is induced by the presence of bulk flavons, which allow for cross-brane interactions and a cross-talk between the quark and neutrino sectors, realizing the spontaneous symmetry breaking pattern A4 --> nothing first proposed in [X.G.\,He, Y.Y.\,Keum, R.R.\,Volkas, JHEP{0604}, 039 (2006)]. We show that the observed quark mixing pattern can be explained in a rather economical way, including the CP violating phase, with leading order cross-interactions, while the observed difference between the smallest CKM entries V_{ub} and V_{td} must arise from higher order corrections. We briefly discuss bounds on the Kaluza-Klein scale implied by flavor changing neutral current processes in our model and show that the residual little CP problem is milder than in flavor anarchic models.