A Falsifiable Trajectory Deviation in the Enchan Screening-Transition Regime

This work presents a prospectively frozen trajectory-level prediction of an effective Enchan Field model in the screening-transition regime. A preceding study showed that a matter-coupled Enchan Field with generic holonomic constraints recovers ordinary Newtonian dynamics in the strongly screened limit. The present work asks the complementary question: when screening becomes incomplete, does the same pre-existing transition prescription produce a concrete trajectory that differs from Newtonian dynamics? Before executing the target orbit, the previously published quadrature response and screening parameters were fixed, together with an isolated point-source boundary, a 5000–15000 AU test orbit, and the first-return apsidal residual as the primary observable. No model parameter was inferred from the resulting trajectory. The protocol was prospectively frozen before numerical execution; this was an internal prospective freeze rather than a public preregistration. Under this explicitly idealized isolated boundary, the frozen Enchan model predicts, relative to an identically initialized Newtonian control: first-return apsidal residual: Δϖ = −0.988030187370 rad first-return period shift: ΔT = −527,101.731125 yr Cartesian separation after one Newtonian period: 4911.350759 AU full three-level numerical spread in Δϖ: 8.44 × 10⁻¹⁵ rad The predicted deviation therefore exceeds the prospectively defined numerical convergence criterion by many orders of magnitude and cannot be absorbed into a simple rescaling of the central mass. The result should not be interpreted as a prediction for an actual Solar-System object. The present calculation assumes an idealized isolated point-source boundary. A Galactic external field and a covariant relativistic/post-Newtonian completion have not yet been frozen. These constitute the next theory step required before comparison with real distant-orbit observations. The accompanying reproducibility package contains the frozen model, prediction protocol, parameter ledger, source code, convergence results, trajectory residuals, and generated figures. Public provenance is explicitly separated from assumptions and effective-completion elements introduced in this work; no private implementation is used as evidence. Licensed under the Enchan Research & Verification License v1.0. The full license text is included in reproducibility_package_v1.0.zip. Version: 1.0Date: August 12, 2026