From UD Theory to the Weak Interaction: Bifurcated Unification and the W/Z Mass Ratio

We derive the electroweak sector from the UD action, based on the bifurcated electroweak unification. The four UD fields are classified by attribute action into the condensate channel (Ud, Dd) and the expansive channel (Uᵤ, Dᵤ). Both channels possess non-zero static stiffness, but the gauge fields of the weak interaction couple exclusively to the condensate channel, acquiring mass and rendering the weak force short-range. The photon, as the gauge field of the expansive channel, does not couple to the condensate stiffness and remains massless. The parameter-free ratio mW/mZ = cosθW is derived directly from diagonalization of the condensate mass matrix, with θW defined through the gauge couplings that are themselves related to the UD structural constant m₀. The chiral V–A structure emerges from the exclusive coupling of weak bosons to the Dd component of the fermion, with right-handed coupling suppressed by the external Ud field disrupting the Dd-Dᵤ bound state. The Higgs boson is identified as a dynamical scalar excitation of the condensate stiffness, with tree-level self-couplings λ₃ = 0 and λ₄ = 0, and mass mₕ² = 2m₀², derived from diagonalization of the full 4 × 4 stiffness matrix. All derivations are self-contained and proceed from the UD axioms.