Covariance-Aware BAO Consistency Test of Energy-Flow Cosmology Using the BOSS DR12 Consensus Likelihood

We test the geometric consistency of the Energy-Flow Cosmology (EFC) modified background expansion against precision baryon acoustic oscillation (BAO) data. Using the official BOSS DR12 consensus likelihood with the full 6×6 covariance matrix (Alam et al. 2017), we compare the EFC background — with DESI DR2-calibrated parameters held fixed — against ΛCDM. Without parameter retuning, EFC yields χ²(6) = 3.4 versus χ²(6) = 5.8 for ΛCDM (Δχ² = −2.4). Both models provide acceptable fits. This is a fixed-parameter consistency test, not a full likelihood fit or model selection analysis. Supplementary cosmic chronometer analysis (25 data points) confirms the geometric consistency (Δχ² = −0.6). No validated geometric channel penalises EFC relative to ΛCDM.