Self-Consistent Vacuum Energy and the Particle Horizon: A Fixed-Point Solution to the Cosmological Constant and Coincidence Problems

This paper is part of a research program proposing that the cosmological constant arises not from total vacuum energy but from the finite-domain residual to which gravity actually couples. This paper develops the fourth component of a research program examining the consequences of finite-domain vacuum energy for the cosmological constant problem. The preceding papers in this series established that gravitational consistency constraints uniquely select a vacuum residual energy density scaling as ρ_Λ ∝ ℏc/(l_p² L²) within a finite causal domain of size L, with an O(1) prefactor α (Paper 3). The present paper demonstrates that this scaling, combined with standard ΛCDM cosmology, defines a self-consistency…