General Theory of Photoproduction on Vector Particles: Universal Vector-Source Formulation and Microscopic Reduction within the L(6+7) Unified Field Framework

This preprint presents a strengthened standalone formulation of photoproduction on vector particles and composite vector sources as the microscopic branch of the L (6+7) unified field framework. The central result is a universal effective conserved vector current JeffμJ^₄₅₅Jeffμ that unifies the vector-meson channel and the composite external-potential channel within a single variational structure, while preserving the standard two-vertex QED lepton-production kernel. In this way, two processes usually treated separately are reformulated as distinct reductions of one common source formalism. The manuscript also clarifies the cross-scale bridge between the microscopic photoproduction sector and the broader L (6+7) program, emphasizing the relation between macroscopic, mesoscopic, and microscopic reductions of one common variational core. A preliminary open-data note on neutrino-sensitive electroweak tails is included only as an exploratory outlook and is not used as a main claim.