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) × 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× 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.
Highlights
The anomalous, axial U(1) symmetries associated with the global symmetries of the hypercolor and SU(N )D dynamics plays the role of the PQ symmetry, producing several dynamical axions
In this paper we have given a UV description of a model that produces a composite Higgs and dynamical axions based on the Sp(2NHC) and SU(4)HC hypercolor gauge groups
For the hypercolor group to be asymptotically free, and confine, requires the colored hyperfermions to be in the fundamental representation of the hypercolor gauge group
Summary
An extended strong sector, where QCD is embedded into a larger gauge group such as SU(N + 3), can solve the strong CP problem with a heavy axion [13, 14]. A critical requirement in constructing such a model is that the hypercolor gauge coupling is asymptotically free and hypercolor confines at low energies. This severely restricts the hyperfermion content of the model and typically favors colored constituents which are in the smallest representation of the gauge group. The SU(5)/SO(5) composite Higgs model is favored because the colored constituents can transform in the fundamental representation of the UV gauge group. To obtain a composite Higgs with a heavy composite axion we will consider extensions of the SU(5)/SO(5) model based on two choices of the hypercolor gauge group: the symplectic group Sp(2NHC) with NHC a positive integer, and SU(4)HC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
