SM-5: Tribimaximal Neutrino Mixing as the Zeroth-Order PMNS Matrix from the K3 Cage Base Graph

Abstract: The three neutrino mass eigenstates are identified as the eigenmodes of the K3 ZBW Hamiltonian. The PMNS neutrino mixing matrix is the change-of-basis between K3 vertex states (charged leptons) and K3 eigenmodes (neutrinos) — exactly the tribimaximal mixing matrix U_TBM. sin²θ₁₂ = 1/3, sin²θ₂₃ = 1/2, sin²θ₁₃ = 0 at zeroth order.