A Composite Higgs with a Heavy Composite Axion

TL;DR

This paper proposes a unified model where a composite Higgs and dynamical axions emerge from strong hypercolor dynamics, solving the strong CP problem and predicting TeV-scale axions detectable at colliders.

Contribution

It introduces a novel composite Higgs model that naturally incorporates dynamical axions and extends the axion mass range without new elementary scalars.

Findings

The model predicts TeV-scale axions accessible at colliders.

It demonstrates spontaneous breaking of an enlarged color group to produce axions.

The framework unifies composite Higgs and axion solutions to the strong CP problem.

Abstract

We consider the strong dynamics associated with a composite Higgs model that simultaneously produces dynamical axions and solves the strong CP problem. The strong dynamics arises from a new $Sp$ or $SU(4)$ hypercolor gauge group containing QCD colored hyperfermions that confines at a high scale. The hypercolor global symmetry is weakly gauged by the Standard Model electroweak gauge group and an enlarged color group, $SU(N+3) \times SU(N)'$. When hyperfermion condensates form, they not only lead to an $SU(5)/SO(5)$ composite Higgs model but also spontaneously break the enlarged color group to $SU(3)_c \times SU(N)_D$. At lower energies, the $SU(N)_D$ group confines, producing two dynamical axions that eliminates all CP violation. Furthermore, small instantons from the $SU(N)'$ group can enhance the axion mass, giving rise to TeV scale axion masses that can be detected at collider experiments. Our model provides a way to unify the composite Higgs with dynamical axions, without introducing new elementary scalar fields, while also extending the range of axion masses that addresses the strong CP problem.