NT15: Robustness of the w_z=11,1991 Minimum and Status of the COCM +wowa Scenario Against DR1 and DR2 Data

This note records the robustness status of the ω_z = 11.1991 minimum and the COCM+w₀wₐ coexistence scenario, based on the quantitative results of P7v6 (doi:10.5281/zenodo.20171261). The minimum is conditional: it is stable in DR1+CC (n=24) with ω_z fixed, but is not recovered by free optimisation on DR2+CC (n=14), which converges to ω_z ≈ 1.5. The COCM+w₀wₐ semi-fixed model gives Δχ² = 6.0 (p = 0.049) over w₀wₐCDM, and Δlog Z = 0.4 in nested sampling — Bayesian evidence is negligible on the Kass–Raftery scale. Both results are consistent with Scenario 1 of P15 (doi:10.5281/zenodo.20413179): COCM and w₀wₐ coexist in the current data, are indistinguishable at DR2 precision, and DR3 is expected to provide the decisive test. The primary pending robustness test is the full DR1 profile χ²(ω_z), computable from the P7v6 deposited code.