Abstract: The strong CP problem — why the CP-violating parameter θ of quantum chromodynamics (QCD) is less than 10⁻¹⁰ — is one of the outstanding puzzles in particle physics. For over four decades, the mainstream solution has relied on introducing a hypothetical axion particle, which has so far not been detected. Starting from Space Ontology, we propose a fundamentally different geometric mechanism: the QCD vacuum is not empty, but a "chiral condensate" with extremely high rigidity. This condensate collectively screens CP-violating perturbations that attempt to distort its internal chiral structure — analogous to the Meissner effect in superconductors expelling magnetic fields. We prove that the physical θ parameter is suppressed by the screening mass Mₛcreen of the chiral condensate via a quartic law: θₚhys ≈ θ₀ · (ΛQCD / Mₛcreen) ⁴ · ξ. Using a large‑N gap equation, we demonstrate Mₛcreen ≈ MPl · e^ (−b/κ), and with the established parameters of the theory — κ = 0. 017, R_κ = 440, and the non-perturbative screening parameter b ≈ 0. 665 — we obtain θ ≈ 1. 6 × 10⁻¹¹. This is in excellent agreement with the current experimental upper bound θ < 1. 5 × 10⁻¹⁰, and is directly testable by next-generation neutron electric dipole moment experiments. This mechanism requires no new particles or symmetries — the "naturalness" of the strong CP problem is not from dynamical relaxation of a symmetry, but from the collective quantum effect of the chiral microstructure of space. It also reveals a profound unified picture: the same κ = 0. 017, through R_κ = 440, amplifies spin-dependent interactions in nuclear forces, and through the chiral condensate, screens the strong CP violation. Amplification and screening are two sides of the same nonlinear dynamics of space. This paper is the fifteenth in the first series (17 papers total) of Space Ontology.
Y L Qiu (Wed,) studied this question.
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