Parameter-Free Triton Mass from D–D Reconstruction in Constrained Null Geometry: Exact Three-Nucleon Recoupling, Connected Möbius Defect, and the 29/32 Reconstruction Amplitude

This work develops a parameter-free derivation of the triton mass within Constrained Null Geometry (CNG), starting from the already fixed CNG deuteron sector and the proton branch of the threshold reaction d + d → t + p. The lowest spatially symmetric three-nucleon sector is fixed by fermionic antisymmetry, yielding the unique triton branch with spin S = 1/2 and isospin I = 1/2. Exact compression of the three embedded deuteron-pair projectors onto this branch produces the rational moments 1/2, 1/8, and 1/32. Their third connected Möbius cumulant gives an irreducible three-body defect of 3/32. Within the primitive local quadratic CNG action, the identity-minus-defect construction then uniquely fixes the reconstruction amplitude to 29/32. Polarization of the two incident deuteron closure cells gives a D–D event release of 4.032015261453865 MeV. Threshold bookkeeping consequently yields a triton binding energy of 8.481135549954681 MeV and a triton mass of 2808.921778871865 MeV/c². The measured triton mass and the measured D–D reaction release are not used as inputs. The empirical triton mass is introduced only after completion of the derivation as an external audit. The resulting difference from the 2022 CODATA triton mass is +0.642192 keV/c², corresponding to a fractional residual of approximately 2.286 × 10⁻⁷. The calculation contains no fitted three-body coefficient, nuclear radius, experimental D–D reaction energy, or triton mass input. The paper therefore provides a parameter-free mass certificate for the A = 3 sector of the primitive quadratic CNG closure and states explicit structural falsification conditions for the construction.