A Flavor Protection for Warped Higgsless Models

TL;DR

This paper develops a realistic 5D higgsless model with a full quark sector, incorporating flavor protection mechanisms, predicting new particles detectable at the LHC, and providing estimates for fermion zero mode approximation errors.

Contribution

It introduces a novel flavor protection scheme in 5D higgsless models, including a new custodially protected representation for the third generation and detailed flavor violation suppression methods.

Findings

Predicts an exotic charge-5/3 quark at ~0.5 TeV detectable at LHC

Demonstrates suppression of flavor-changing neutral currents below experimental bounds

Provides quantitative estimates for fermion zero mode approximation errors

Abstract

We examine various possibilities for realistic 5D higgsless models and construct a full quark sector featuring next-to-minimal flavor violation (with an exact bulk SU(2) protecting the first two generations) satisfying electroweak and flavor constraints. The "new custodially protected representation" is used for the third generation to protect the light quarks from flavor violations induced due to the heavy top. A combination of flavor symmetries, and RS-GIM for the right-handed quarks suppresses flavor-changing neutral currents below experimental bounds, assuming CKM-type mixing on the UV brane. In addition to the usual higgsless RS signals, this model predicts an exotic charge-5/3 quark with mass of about 0.5 TeV which should show up at the LHC very quickly, as well as nonzero flavor-changing neutral currents which could be detected in the next generation of flavor experiments. In the course of our analysis, we also find quantitative estimates for the errors of the fermion zero mode approximation, which are significant for higgsless-type models.