Grand Color Axion

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 angle can also arise, in our model as well as in a large class of heavy axion scenarios, from non-renormalizable Peccei-Quinn-conserving interactions, which introduce a new "heavy axion quality problem". Our model has a very minimal field content, it relies entirely on gauge invariance and does not require the introduction of additional symmetries beyond the usual one postulated by Peccei and Quinn. The phenomenology is very rich and can be tested at colliders as well as via cosmological observations. A particularly interesting portion of parameter space predicts a visible axion of mass above the GeV and decay constant larger than a few TeV.

18 pages plus appendix, 1 figure. v2: minor corrections. Accepted for publication in JHEP

References in corpus (2)

• Anomalous solutions to the strong CP problem
• Enhanced EDMs from Small Instantons

Cited by in corpus (16)

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• High Quality Axion in Supersymmetric Models
• Non-Invertible Peccei-Quinn Symmetry, Natural 2HDM Alignment, and the Visible Axion
• Sensitivity to Kaon Decays to ALPs at Fixed Target Experiments
• ALP-ine quests at the LHC: hunting axion-like particles via peaks and dips in $t\bar{t}$ production
• Search for a Hidden Sector Scalar from Kaon Decay in the Di-Muon Final State at ICARUS
• A Light QCD Axion with Hilltop Misalignment
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• No Warm Inflation From a Vanilla Axion
• (Non-)Perturbative Dynamics of a Light QCD Axion: Dark Matter and the Strong CP Problem
• New Bounds on Heavy QCD Axions from Big Bang Nucleosynthesis
• Finding BSM Needles in Electromagnetic Haystacks at DUNE