The 13.7-Degree Attractor: The Mechanical Lock-In Angle of the Lepton Triangle in Tensor Field Dynamics

This paper investigates the value 13.7 degrees as a distinguished mechanical lock-in angle of the lepton triangle within the framework of Tensor Field Dynamics (TFD). The analysis starts from an amplitude-based representation of the leptons, from which a characteristic angle is derived under a static equilibrium condition. Numerical evaluation yields a value of approximately 13.704204 degrees, which is presented in condensed publication form as the 13.7-degree attractor. The paper further embeds this angle locally into the stationary hardware sector of the TFD field equation. In this description, the lock-in state appears as the null direction of the transverse residual drive. In addition, the projection 13.7 ↔ 1.37 ↔ 137 is introduced as an explicit resonance structure associated with the published attractor value. The result is a closed TFD formulation that combines mechanical derivation, local field-mechanical embedding, and defined resonance projection within a single formal framework.