This work develops a fully mechanical explanation of the leptonic sector within Quarkbase Cosmology. By modeling the electron, muon, and tau as the three normal modes of a neutral Qb–antiQb compactation pair coupled to the radial mode of a finite-range Ψ-field, the existence of exactly three charged leptons and their mass hierarchy emerges as a structural property of the medium. No Yukawa couplings or intrinsic mass parameters are required.The framework also embeds neutrino oscillations, vacuum quantization, and potential mechanisms for matter–antimatter imbalance as natural consequences of the same resonator structure. This establishes a unified, medium-based interpretation of leptons as vibrational excitations of a continuous physical field, providing predictive coherence across particle physics, vacuum mechanics, and cosmology.