A Solution to the Flavor Problem of Warped Extra-Dimension Models

TL;DR

This paper proposes a minimal extension to warped extra-dimension models that alleviates flavor violation issues, allowing for lower KK scales around 2 TeV compatible with experimental constraints, and predicts new particles observable at colliders.

Contribution

Introducing an extended gauge symmetry in warped models to solve the flavor problem without fine-tuning and predicting new collider-accessible particles.

Findings

KK scale ~2 TeV consistent with flavor constraints

Extended Higgs sector with color-octet scalars

Predicted resonances compatible with LHC bounds

Abstract

A minimal solution to the flavor problem of warped extra-dimension models, i.e. the excessive mixed-chirality contribution to CP violation in K-Kbar mixing arising from Kaluza-Klein (KK) gluon exchange, is proposed. Extending the strong-interaction gauge group in the bulk by an additional SU(3), and breaking this symmetry to QCD via boundary conditions, the constraints arising from the epsilon_K parameter are significantly relaxed. As a result, KK scales M_KK ~ 2 TeV are consistent with all flavor observables without significant fine-tuning. The model predicts the existence of an extended Higgs sector featuring massive color-octet scalars and a tower of KK pseudo-axial gluon resonances, whose existence is not in conflict with recent LHC dijet bounds.