Measuring the MOND Acceleration Scale at High Redshift: The Baryon-Calibration Wall

The programme ties the MOND acceleration scale to the vacuum, a0 = kappa c sqrt(G rho_Lambda), with kappa = 1/2 fitted, not derived. Its distinctive high-redshift prediction is a flat a0(z); the rival is a0 proportional to H(z) (about x2.2 at z~1.4, x8 at z~5); LambdaCDM has no a0 and enters only through an effective-a0 proxy. We collect the programme's committed high-redshift a0 lanes and state one result plainly: in every lane the limit that does not shrink with sample size is the absolute calibration of the baryon (gas and stellar) masses, and it is the binding one. The lever. Where the discs sit (g_bar/a0 = 1.1 to 4.4) a 0.05 dex error in the mass discrepancy is a factor 1.5 to 1.8 in a0. In the deep regime an amplitude test measures only the product of the calibration and a0. Lean theorems (ChainCert, 331 theorems) show that a0 remains identifiable in principle for the exact kernel, but the estimate is ill-conditioned: with the calibration free, sigma(log a0) >= 3 sigma/sqrt(N) for any sample, and a sample of 20 galaxies at 0.1 dex must reach g_bar/a0 of about 8 and include deep points to measure a0 to 0.1 dex. The samples. No sample separates the laws: RC100 is gas-route-limited, CRISTAL is route-dependent, and the z = 2-5 compilation, the ALMA [CII] rotators and seven class-M galaxies are NOT POSSIBLE at pre-flight. The gas calibration at z~2.2 is a prescription bracket (~0.2-0.7 dex), and no public dynamics-independent anchor reaches 0.10 dex: the best route, an absorption-line alpha_[CI](Z) relation, scatters 0.64 dex about its own fit in its own table against the 0.2 dex it states. A within-survey lens-redshift split of the KiDS-1000 lensing RAR, which would cancel a common-mode calibration, is NOT POSSIBLE (power 0.14 against 9) and non-discriminating by its own control, because a stellar-mass drift delta mimics an a0 drift by delta/2. Bottom line. A decisive test needs baryon errors and band at or below 0.10 dex. With the public data on hand the question is open; nothing here is a detection either way, and nothing here says the data favour the framework, the rival or LambdaCDM. The decisive near-term test of the programme is a separate z = 0 one: Gaia DR4 wide binaries (2 December 2026). Every quoted number is re-read from committed files by PAPER38_audit.py (293 of 293). AI-assisted research programme; not peer reviewed; nothing is claimed closed.