Composite Higgses with seesaw EWSB

TL;DR

This paper proposes a novel Composite Higgs model where electroweak symmetry breaking occurs via a seesaw mechanism involving sequential global symmetry breaking, which reduces fine-tuning and allows heavier top partners.

Contribution

It introduces a new class of Composite Higgs models with a seesaw-like EWSB mechanism and analyzes the resulting Higgs potential and phenomenological implications.

Findings

Seesaw-like EWSB mechanism can induce negative mass-squared for the Higgs.

Extra symmetry breaking scale alleviates fine-tuning issues.

Model allows for higher mass bounds on top partners.

Abstract

We introduce a new class of Composite Higgs models in which electroweak symmetry is broken by a seesaw-like mechanism. If a global symmetry is broken sequentially at different scales, two sets of pseudo-Goldstone bosons will arise, one set being typically heavier than the other. If two Composite Higgs doublets mix, then the mass-squared of the lighter state can be driven negative, and induce EWSB. We illustrate with the example $SO(6) \rightarrow SO(5) \rightarrow SO(4)$, and derive an estimate of the light Higgs potential. We find that the introduction of an extra scale can ease many of the tensions present in conventional Composite Higgs models, especially those related to fine-tuning. In particular we find that we can significantly raise the upper bound on the mass of the elusive top partners.