Mirror-Fractal Dark Sector Cosmology

The standard Lambda Cold Dark Matter model remains the benchmark framework for precision cosmology, yet it faces persistent tensions involving the Hubble constant, the amplitude of late-time clustering, and the physical interpretation of the dark sector. This paper develops and audits a Mirror-Fractal Dark Sector model derived from the Fractal Consistency Law (FCL) and its Principle of Minimal Inconsistency (PMI). The model treats dark matter and dark energy not as independent substances but as two geometric manifestations of a two-layer CPT/PAF architecture: Fractal Curvature Matter (MCF) is modeled as local boundary memory projected from a mirror-fractal layer, whereas Residual Fractal Tension (RFT) is modeled as global inter-layer tension. The theoretical construction is translated into an effective tabulated equation of state, w(a), and tested through compressed-likelihood and CAMB-level proxy audits. The final reproducibility audit uses five independent random seeds, 25,000 fast FCL prefilter candidates, and 50 CAMB-refined tabulated-background candidates. It recovers 28 safe CAMB candidates across all five seeds, satisfying simultaneously H0 ≥ 70 km s−1 Mpc−1, 0.75 < S8 < 0.80, χ²BAO < 25, and χ²RSD < 10. The best safe candidate yields H0 = 70.017, Ωm = 0.282, σ8 = 0.786, S8 = 0.762, χ²BAO = 14.73, χ²RSD = 7.77, and χ²total = 31.47. These results do not establish final empirical validation of the FCL-CPT/PAF model, but they provide strong methodological evidence that the model possesses reproducible CAMB-level viable regions. The paper should be read as a compressed-likelihood and CAMB-proxy reproducibility audit, not as a final full-likelihood cosmological inference, not as a native perturbation-level Boltzmann implementation, and not as definitive replacement of ΛCDM.