On the Symmetric Structure of Relativistic Matter and Its Gravitational Response

We propose an algebraic framework to reinterpret the source term linking relativistic matter and gravity. By enforcing a decomposition of the Dirac field based on Charge-Conjugation (C) symmetry, we establish the "bi-particle" - an irreducible symmetric excitation effective above the Compton scale - as the fundamental ontological unit of gravitation. The Energy-Momentum Tensor is shown to separate rigorously into C-even diagonal terms (mass source) and C-odd cross terms (charge source). In macroscopic neutral matter, C-symmetry necessitates the vanishing of these cross-terms, leaving the positive-definite symmetric sector as the sole gravitational contributor. This perspective resolves the standing conceptual tension between QFT localization limits and the Weak Equivalence Principle, while recovering Maxwellian electrodynamics via the mixing sector. Furthermore, it introduces a susceptibility parameter for the symmetric sector, rendering the theory falsifiable through mass measurements in macroscopic quantum coherent systems.