We present a covariance-aware global fit of six precision CKM observables—spanning superallowed and neutron β decays, kaon semileptonic and leptonic determinations of Vus, and two independent τ -based extractions—testing the hypothesis that a scale-dependent effective weak coupling, as predicted by Open Effective Field Theory (Open-EFT), resolves the 3.29σ Cabibbo angle anomaly.Our minimal ansatz introduces a single running parameter ϵVus governing a logarithmic scale dependence of the extracted |Vus|eff (μ). For the conservative configuration (ρτ = 0.50, μref = 0.2 GeV), the best fit yields ϵVus ≃ 1.33 × 10−2 with ∆χ2 = 13.62. A frequentist calibration using 2 × 106 toy Monte Carlo pseudo-experiments, incorporating a trials factor to correct for the look-elsewhere effect over μref , yields an empirical global significance of Zemp = 3.29σ (p = 5.055 × 10−4), validated independently by Extreme Value Theory extrapolation (ZEVT = 3.29σ). In the nominal uncorrelated scenario, the significance reaches Zemp = 3.82σ.Jackknife leave-one-out tests (∆χ2 > 6.13 under all removals), functional discrimination strongly preferring logarithmic over power-law deformations, and a model-independent Gaussian Process reconstruction with Bayes Factor BF = 47 (“very strong” on the Jeffreys scale) confirm the robustness and physical specificity of the signal. An inverse Källén–Lehmann spectral reconstruction reveals a broad continuum rather than isolated poles, directly supporting the dissipative Open-EFT mechanism. We interpret these results as strong evidence for a scale-dependent effective wave-function normalization providing a compact, falsifiable resolution to the Cabibbo angle anomaly.
Ahmed Beniaiche (Sat,) studied this question.