Constraints on Loop Quantum Gravity Predictions for the Cosmological Constant from Phenomenological Integration and Bounded Parameter Scans

We present a falsifiability-oriented workflow for confronting loop-quantum-gravity (LQG)-inspired vacuum-energy estimates with late-time cosmological targets. Using a modular "cosmological-constant workbench" and a lightweight integration layer, we incorporate an external LQG cosmological-constant predictor as a target generator and evaluate its implied vacuum energy density $\rho_{\rm vac}$ against the observed dark-energy density $\rho_{\Lambda,0}$. We then perform bounded scans over a small, natural-parameter grid (108 evaluations) covering polymer and phenomenological coefficients. Across this bounded domain, we find a persistent mismatch of at least $\sim 150$ orders of magnitude in $\rho_{\rm vac}/\rho_{\Lambda,0}$. Within this regime, the predictor does not naturally resolve the cosmological-constant hierarchy without additional tuning or new ingredients. The scan therefore provides an empirical no-go style constraint on the current formulation of this class of LQG-inspired vacuum-energy calculations.