Distinguishing Higgs models in H→bb̄/H→τ+τ−

We analyze the ratio of branching ratios R=BR(H→bb̄)/BR(H→τ+τ−) of Higgs boson decays as a discriminant quantity between supersymmetric and nonsupersymmetric models. This ratio receives large renormalization-scheme independent radiative corrections in supersymmetric models at large tanβ, which are absent in the Standard Model or Two-Higgs-doublet models. These corrections are insensitive to the supersymmetric mass scale. A detailed analysis in the effective Lagrangian approach shows that, with a measurement of ±21% accuracy, the Large Hadron Collider can discriminate between models if the CP-odd Higgs boson mass is below 900 GeV. An e+e− Linear Collider at 500 GeV center of mass energy can discriminate supersymmetric models up to a CP-odd Higgs mass of ∼1.8 TeV.