Search for charged Higgs bosons in top quark decays

We present a search for charged Higgs bosons in top quark decays. We analyze the e+jets, μ+jets, ee, eμ, μμ, τe and τμ final states from top quark pair production events, using data from about 1 fb−1 of integrated luminosity recorded by the DØ experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a τ lepton and a τ neutrino and a third one where both decays appear. We extract limits on the branching ratio B(t→H+b) for all these models. We use two methods, one where the tt¯ production cross section is fixed, and one where the cross section is fitted simultaneously with B(t→H+b). Based on the extracted limits, we exclude regions in the charged Higgs boson mass and tanβ parameter space for different scenarios of the minimal supersymmetric standard model.