Gaia wide binaries test gravity below the MOND acceleration scale with no possible dark matter involvement. Chae reports a 20 percent velocity boost over Newton (gamma = 1.43 +/- 0.06), Hernandez concurs; Banik et al. report a 19σ Newtonian preference from a different selection, and the dispute hangs on triples, eccentricities, and modeling choices. ΛCDM needs Newton to win but offers no insight either way.
ΛCDM attributes all galactic-scale gravitational anomalies to particle halos, so it must predict exact Newtonian behavior in two-body systems. If a boost is confirmed where no halo can reach, the model loses its rationale: the acceleration-scale phenomenology it explains with dark matter would be appearing without any.
SCT replaces the dark matter particle with constructive gravitational superposition of many comoving sources (P50), and the mechanism has a hard structural requirement: amplification grows with the number of coherently comoving bodies, A(N, σ_v, R), and collapses to exactly 1 as N goes to 1, where standard GR is recovered without correction (P53). A wide binary is an N = 2 system with no comoving ensemble to cohere with: SCT therefore predicts pure Newtonian dynamics in wide binaries, cleanly and without tuning. SCT sides with the null result, and does so before the dispute is settled.
This makes wide binaries one of the sharpest discriminating tests on the board, because the three frameworks split three ways: particle dark matter predicts Newton (halos absent), MOND predicts the boost (acceleration-scale law), and SCT predicts Newton for a structural reason MOND cannot imitate, while still reproducing the galactic-scale phenomenology MOND was built for through ensemble coherence (the same A that gives flat rotation curves and the radial acceleration relation at N large). The low-acceleration coincidence is repartitioned: in SCT the relevant variable is coherent source count, not acceleration, and wide binaries are where the two variables decouple.
There is no need to invoke modified force laws, and no embarrassment if Newton wins: that outcome is SCT's registered expectation.
The kill is symmetric and explicit. A community-confirmed gravity boost of gamma near 1.4 in clean, triple-purged, genuinely two-body wide binaries would falsify SCT's coherence mechanism outright, since N = 2 systems must be Newtonian if dark-matter phenomenology comes from ensemble superposition; MOND would win that world. Conversely, a confirmed null result eliminates acceleration-scale modified gravity and leaves the ensemble-coherence and particle-halo explanations standing, to be separated by the cluster-scale tests where they differ.