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arXiv · 2510.17370

High Quality QCD Axion in the Standard Model

Jie Sheng·Tsutomu T. Yanagida
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Abstract

Although the axion is the most compelling solution to the strong CP problem, the ad hoc introduced global Peccei-Quinn symmetry suffers from a severe fine-tuning problem known as the quality problem. In this Letter, we show that the discrete gauge symmetry $\mathbb Z_4 \times \mathbb Z_3$ motivated from the internal structure of the Standard Model can naturally predict a high-quality axion, leading to a distinct and testable parameter space. Remarkably, this minimal framework simultaneously accounts for neutrino masses, baryon asymmetry, and dark matter.

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Jie Sheng, Tsutomu T. Yanagida. 2025-10-20. High Quality QCD Axion in the Standard Model. https://doi.org/10.1103/h9ws-xgst

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