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arXiv · 2406.01689

Solving the strong CP problem without axions

Ferruccio Feruglio·Matteo Parriciatu·Alessandro Strumia·Arsenii Titov
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Abstract

We formulate general conditions under which the strong CP problem is solved by spontaneous CP violation. Quark-mass matrix elements are polynomials in the CP-breaking order parameters, engineered such that their determinant is a real constant. This scheme permits only a limited number of textures. These conditions can be realized in supersymmetric theories with CP as an anomaly-free local flavour symmetry, suggesting a unified solution to the strong CP problem and the flavour puzzle. Our solution can be implemented using either modular invariance or a local U(1) symmetry. We present modular-invariant realizations where matter fields are assigned small modular weights $\pm2$ ($\pm1$), utilising higher levels $N=2$ ($N=3$). Heavy quarks are in general not required, but their presence allows for models where colored particles fill non-singlet representations of the flavour group.

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Ferruccio Feruglio, Matteo Parriciatu, Alessandro Strumia, Arsenii Titov. 2024-06-03. Solving the strong CP problem without axions. https://arxiv.org/abs/2406.01689

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