New Topflavor Models with Seesaw Mechanism

TL;DR

This paper introduces new topflavor models where the third family quarks experience a new gauge force, naturally generating top and bottom masses via a seesaw mechanism, with small corrections to electroweak parameters and collider signatures analyzed.

Contribution

It presents a novel class of topflavor models with a seesaw mechanism for quark mass generation and discusses their phenomenological implications.

Findings

Small contributions to (S,T,U) parameters and Zbb vertex.

Viable flavor mixing patterns suppressing flavor-changing effects.

Predictions for collider signatures of light Higgs and top quark.

Abstract

New class of models are constructed in which the third family quarks, but not leptons, experience a new SU(2) or U(1) gauge force. Anomaly cancellation enforces the introduction of spectator quarks so that the top and bottom masses are naturally generated via a seesaw mechanism. We find the new contributions to the (S,T,U) parameters and Zbb vertex to be generically small. We further analyze how the reasonable flavor mixing pattern can be generated to ensure the top-seesaw mechanism and sufficiently suppress the flavor-changing effects for light quarks. Collider signatures for the light Higgs boson and top quark are also discussed.