USSFT Paper XVI: Experimental Tests and Observational Predictions: A Systematic Catalog of Falsifiable Contact with Observation

This paper provides a systematic, honest catalog of all experimental and observational predictions generated by the USSFT framework (Papers I-XV). We classify predictions into three categories: (i) Consistency predictions that reproduce known physics (general relativity and quantum mechanics) and serve as necessary but not sufficient tests of the framework; (ii) Distinguishing predictions that are unique to USSFT and could in principle separate it from standard physics, though most are currently Planck-suppressed beyond foreseeable experimental sensitivity; and (iii) Future-derivable predictions whose magnitudes depend on quantities not yet computed from first principles (status (C) ), but which become sharp, falsifiable tests once those computations are completed. We compute explicit magnitudes where the underlying derivations specify them and where a clean EFT estimate is possible. Distinguishing predictions catalogued include the structural prohibition of linear (n=1) Lorentz invariance violation, the absence of macroscopic fifth-force signatures, GR-identical black hole exteriors at all foreseeable measurement precisions, and the inflationary CMB observables ns approximately 0. 957-0. 964 and r approximately 0. 003-0. 006 derived from the locked Lagrangian via the xi-inflation mechanism (Paper XIII), with the ratio lambdaU/xi² approximately 5e-10 fixed by the Planck scalar amplitude. The inflation predictions are shared with the universal-attractor class (Higgs and Starobinsky inflation) ; what is structurally distinguishing for USSFT is the locked Lagrangian generating these without new fields or parameters, the discrete lattice supplying a candidate UV completion of the unitarity-bound sector, and the hypercubic NLO operator predicting cubic-symmetric statistical anisotropy aligned with the lattice axes. The result is a transparent assessment of where USSFT makes contact with observation today, and a concrete roadmap for where it can do so in the future. This work is part of the USSFT 18-paper series; readers are referred to Paper XIII (DOI: 10. 5281/zenodo. 19690230) for the inflation derivation and to Paper 0 (DOI: 10. 5281/zenodo. 19477839, published in IJQF Vol. 12 Issue 2, 2026) for the framework foundations.