Mass Field Momentum Coupling Theory (IV) — Dynamical Derivation of the Weak Interaction

The weak interaction is a short-range interaction that induces particle flavor change and violates parity conservation. Its standard description is based on the electroweak unification theory and Fermi’s four-fermion interaction. Within the framework of the mass field momentum coupling theory, this paper takes the uneven flavor charge distribution as the core premise and incorporates the weak interaction into the unified description of "uneven matter distribution + motion coupling". The research shows that the weak interaction can be regarded as the momentum coupling force generated by the coupling between a particle moving in an inhomogeneous flavor charge field and the field gradient, whose extremely short-range property is determined by the exponential decay form of the flavor charge field. The tangential component dominates the flavor-changing process, and chiral coupling explains parity non-conservation. The dynamical form derived is consistent with Fermi’s weak interaction theory under low-energy approximation, and agrees with experimental data such as the neutron β-decay lifetime. This paper incorporates the weak interaction into the mass field momentum coupling system, completing the unified formal description of the four fundamental interactions.