Cosmological Scars: Precision Constraints on Vacuum Energy Sequestering from the Higgs Portal

Vacuum Energy Sequestering (VES) offers a technically natural ap-proach to the cosmological constant problem by enforcing global con-straints that decouple vacuum loop contributions from spacetime curva-ture. We classify VES ultraviolet (UV) completions by their low-energyEffective Field Theory (EFT) imprints. ”Class A” (clean) embeddingsgenerate no collider-accessible SMEFT operators, while ”Class B” embed-dings with Higgs-coupled heavy mediators induce a correlated dimension-6Higgs-sector scar. For a heavy singlet portal, tree-level matching yields arigid relation between the Warsaw-basis operators QH□ = (H†H)□(H†H)and QH = (H†H)3, implying a falsifiable ”scar line” in observable space:...