The 5:4 Resonance Hypothesis: Cosmological Constant from Rotational Resonance between Cosmic Flows and Hubble Expansion — Triple Spin Framework Paper 4

We report a previously unidentified connection between the residual Hubble tension and a near-exact 5:4 resonance in the Triple Spin Framework (Papers 1-3, Corales 2026). The critical viscosity η* at which the cosmological constant Λ is recovered exactly satisfies η* = 1.270 ± 0.026 ≈ 5/4, consistent with the 5:4 resonance at 0.78σ. Using a weighted average of six independent measurements spanning 1988-2023, we obtain v₂ = 629 ± 18 km/s for the Great Attractor infall velocity. The Great Attractor behaves as a damped harmonic oscillator (Tennis Racket Theorem / Dzhanibekov effect) with period T_GA = 0.749 Gyr, naturally explaining the H₀(z) oscillation detected by Jia et al. (2023) at 5.6σ. Main results:→ Residual 0.46σ tension is the signature of the 5:4 resonance not yet resolved→ GA is a cosmic damped harmonic oscillator→ ζ = 0.030 (underdamped)→ Λ emerges from 5:4 resonance between cosmic rotation and Hubble expansion Falsifiable prediction:DESI DR2 (2026) will measure v₂ = 643 ± 20 km/s → η* = 5/4 exactly → Hubble tension = 0.000σ → Λ has mechanical origin. Zero free parameters. Related:Paper 1: doi.org/10.5281/zenodo.18809238Paper 2: doi.org/10.5281/zenodo.18809884Paper 3: doi.org/10.5281/zenodo.18827877