Flavor Alignment via Shining in RS

TL;DR

This paper introduces a warped extra-dimensional model with flavor alignment that suppresses flavor violation, potentially allowing for a low Kaluza-Klein scale observable at the LHC, but faces challenges from radiative corrections and experimental bounds.

Contribution

The paper proposes a novel flavor alignment mechanism in warped extra-dimensional models that reduces flavor violation and enables a low KK scale, with detailed analysis of radiative effects and bounds.

Findings

Flavor violation can be suppressed to allow TeV-scale KK modes.

Radiative corrections induce flavor misalignment, constrained by experiments.

Adjustments in flavon VEVs or extended Higgs sectors can mitigate flavor effects.

Abstract

We present a class of warped extra dimensional models whose flavor violating interactions are much suppressed compared to the usual anarchic case due to flavor alignment. Such suppression can be achieved in models where part of the global flavor symmetry is gauged in the bulk and broken in a controlled manner. We show that the bulk masses can be aligned with the down type Yukawa couplings by an appropriate choice of bulk flavon field representations and TeV brane dynamics. This alignment could reduce the flavor violating effects to levels which allow for a Kaluza-Klein scale as low as 2-3 TeV, making the model observable at the LHC. However, the up-type Yukawa couplings on the IR brane, which are bounded from below by recent bounds on CP violation in the D system, induce flavor misalignment radiatively. Off-diagonal down-type Yukawa couplings and kinetic mixings for the down quarks are both consequences of this effect. These radiative Yukawa corrections can be reduced by raising the flavon VEV on the IR brane (at the price of some moderate tuning), or by extending the Higgs sector. The flavor changing effects from the radiatively induced Yukawa mixing terms are at around the current upper experimental bounds. We also show the generic bounds on UV-brane induced flavor violating effects, and comment on possible additional flavor violations from bulk flavor gauge bosons and the bulk Yukawa scalars.