The Universe Force & Mirror Universe Unified Theory — Version 5: A Derived, Testable, Self-Correcting Two-Brane Radion Framework

Version 5 of the Universe Force & Mirror Universe framework presents a classical five-dimensional stabilized two-brane scalar–tensor model together with a matched low-energy four-dimensional effective field theory. The construction contains a warped five-dimensional bulk, a visible Positive Brane, a hidden Mirror Brane, a bulk stabilization scalar, and a physical radion identified with the lowest coupled scalar–gravity eigenmode. The work derives the stabilized background, brane matter couplings, radion-mediated interactions, cosmological background and perturbation equations, effective gravitational couplings, and warped tensor Kaluza–Klein spectrum. Several internal calculations have been independently reproduced. The homogeneous FLRW five-dimensional Ricci reduction has been checked through a direct Christoffel–Riemann–Ricci calculation. The pure-RS dimensional-reduction formulas have been checked symbolically. The first five tensor KK benchmark masses have been reproduced using three numerically distinct methods: finite-element generalized eigenvalue analysis, direct ODE shooting, and finite-difference generalized eigenvalue analysis with the expected convergence. The analysis also produces negative results. Earlier spin-1 gravity, negative-mass Mirror matter, direct Visible–Mirror material transfer, and Gaussian KK-resonance Early Dark Energy mechanisms are not retained in the final model because they are not derived from the Version-5 microscopic framework. A scale-separated cosmological branch requires an extremely small stabilization parameter, approximately \(l~10⁻²⁴\), with geometric backreaction \(ε~10⁻⁴⁹\). The limit \(l→0\) restores an exact classical \(Z_2:χ→-χ\) symmetry, providing a possible technical-naturalness interpretation for the small classical source. The quantum radiative stability of the ultra-light radion remains unresolved. The manuscript explicitly distinguishes assumptions, derivations, independent verification, provisional numerical results, rejected hypotheses, predictions, and observations.