Constraints on Two-Higgs Doublet Models at Large tan{beta} from W and Z decays

Abstract

We study constraints on type-II two Higgs doublet models at large tan{beta} from LEP/SLD Z-pole data and from lepton universality violation in W decay. We perform a global fit and find that, in the context of Z decay, the LEP/SLD experimental values for lepton universality violation, R_b, and A_b all somewhat disfavor the model. Contributions from the neutral Higgs sector can be used to constrain the scalar-pseudoscalar Higgs mass splittings. Contributions from the charged Higgs sector allow us to constrain the charged Higgs mass. For tan{beta}=100 we obtain the 1 sigma classical (Bayesian) bounds of m_{H+} > 670 GeV (370 GeV) and 1 > m_{h0}/m_{A0} > 0.68 (0.64). The 2 sigma bounds are weak. Currently, the Tevatron experimental limits on lepton universality violation in W decay provide no significant constraint on the Higgs sector.