An Empirical Mass Relation among Electroweak Bosons: mH mZ² ≈ 2 mW³

We report a numerical relation among the masses of the Standard Model electroweak bosons: mH × mZ² ≈ 2 mW³ Using the latest Particle Data Group values (mH = 125. 1 GeV, mZ = 91. 1876 GeV, mW = 80. 379 GeV), this relation is satisfied to 0. 16% accuracy, and the dimensionless ratio I ≡ mH mZ²/mW³ takes the value Iₑxp = 2. 003. We emphasize that this relation is NOT a theoretical identity of the Standard Model: it is equivalent to the empirical near-equality λ ≈ g² cos⁴θW / 2 (accurate at ~2. 4%), where λ is the Higgs self-coupling and θW is the Weinberg angle. The relation is therefore analogous in status to the Koide formula for charged-lepton masses---a precise empirical regularity awaiting theoretical explanation. We document the numerical accuracy, the equivalent forms, and discuss possible theoretical avenues including extended custodial symmetry, gauge-Higgs unification, and conformal extensions of the Standard Model.