Grand Color Axion
Alessandro Valenti, Luca Vecchi, Ling-Xiao Xu

TL;DR
This paper introduces a heavy axion model embedded in a Grand Color framework that naturally relaxes the axion's vacuum expectation value, addressing the strong CP problem with minimal field content and rich testable phenomenology.
Contribution
It proposes a novel heavy axion model within a Grand Color structure that reduces the axion quality problem and requires no extra symmetries beyond Peccei-Quinn.
Findings
The axion mass can be above the GeV scale.
The model predicts observable collider and cosmological signatures.
The axion potential is dominated by a new confining scale, reducing sensitivity to the QCD contribution.
Abstract
We present a model that solves the strong CP problem via an axion parametrically heavier than the standard one. Within this picture the Standard Model quarks are embedded into a larger non-abelian Grand Color group that at high scales splits into ordinary QCD and an additional confining dynamics under which exotic chiral fermions are charged. Crucially, the vacuum expectation value of the axion is automatically relaxed to zero because the only renormalizable source of explicit CP violation, beyond those encoded in the topological angles, is contained in the Standard Model Yukawa couplings, and is therefore very suppressed. The axion potential is controlled by the scale of the new confining group and is much larger than the QCD contribution, such that its dynamics is less exposed to the so-called "axion quality problem". Potentially observable corrections to the effective topological…
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Taxonomy
TopicsDark Matter and Cosmic Phenomena · Particle physics theoretical and experimental studies · Cosmology and Gravitation Theories
