Muon Decay and the Problem of Lepton Stability

Muon decay is described with high quantitative accuracy in the Standard Model as a weak interaction process, yet the deeper origin of muon instability—contrasted with the absolute stability of the electron—remains mechanistically opaque. This paper proposes a geometric–dynamical interpretation in which charged leptons are modeled as persistent circulation structures embedded in a four-dimensional rotational flow, with stability determined by the ability to maintain exact global phase closure. Within this framework, the electron corresponds to an exactly phase-closed configuration and is therefore stable, while the muon is only near-closed and exhibits slow internal phase drift that inevitably accumulates to a threshold requiring reconfiguration. Muon decay is interpreted as a controlled topological unwinding that restores exact phase closure by relaxing into the electron state, with neutrinos carrying away residual phase mismatch. The observed decay channel, lifetime, environmental invariance, and relativistic time dilation emerge naturally from this picture without modifying Standard Model decay phenomenology. A unified explanation of the charged-lepton hierarchy follows directly from scale-dependent phase-closure constraints. Finally, the paper outlines conservative, falsifiable predictions that distinguish internal geometric instability from interaction-driven decay, emphasizing invariances, absences, and correlations accessible to existing experimental techniques.