Dark Energy from Equal Creation and Destruction Rates: Parameter-Free Resolution of the Cosmological Constant Problem in the U-Cell Model

Ω_Λ We derive the dark energy fraction from the U-Cell Model (UCM), an elastic-substrate framework from which gravity and Lorentz symmetry emerge without fine-tuning. A cell-number conservation law — analogous to crustal balance in plate tectonics — partitions the cosmic substrate into voids (sources) and halos (sinks), yielding ΩΛ, 0=22+2−π/2=0, 6834, , ₀ = 22 + 2-/2 = 0, 6834, ΩΛ, 0=2+2−π/22=0, 6834, in agreement with Planck 2018 to 0, 19 %. The Hubble constant cancels identically in the balance, so the derivation fixes the same value of ΩΛ, 0, ₀ ΩΛ, 0 at every epoch; the time-dependent dark-energy fraction ΩΛ (z) _ (z) ΩΛ (z) follows the standard Friedmann equation, which is itself derived from the UCM substrate via Paper 6 of the UCM series. The dark-energy equation of state is w=−1w = -1 w=−1 exactly (constant density ρΛ_ ρΛ). The balance is dynamically stable through negative feedback: cells created in voids are the inflow consumed by halos, just as crust created at mid-ocean ridges is the plate subducted at trenches. Theorem 1 resolves the cosmological constant problem structurally: vacuum zero-point energy exists but is gravitationally inert because it produces no gradient in the substrate flow, and its magnitude therefore does not enter the Einstein equations. The single algebraic constant fcold=2−π/2≈0, 6551fcold = 2-/2 0, 6551 fcold=2−π/2≈0, 6551 links galactic rotation curves (153 SPARC galaxies, χ~median2=0, 73²ₘedian = 0, 73 χ~median2=0, 73) to the global energy budget of the universe across six orders of magnitude in mass. Nine independent cosmological probes (six geometric distance measurements, three CMB observables) are jointly consistent with the parameter-free prediction at cumulative ΣΔBIC=+19, 3 = +19, 3 ΣΔBIC=+19, 3 in favour of the UCM over best-fit Planck Λ ΛCDM (Paper 24). UCM preprint series, Paper 1 (revised). Companion to Paper 43 (Dark Matter as Convergence-Induced Substrate Wrinkling).