Search for Charged Higgs Bosons in Decays of Top Quark Pairs

We present a search for charged Higgs bosons in decays of pair-produced top quarks using 109.2±5.8pb^-1 of data recorded from pp̄ collisions at √s0ex0ex=0ex0ex1.8TeV by the D0 detector during 1992--1996 at the Fermilab Tevatron. No evidence is found for charged Higgs production, and most parts of the [M_H⁺,tanβ] parameter space where the decay t→H⁺b has a branching fraction close to or larger than that for t→W⁺b are excluded at $95%$ confidence level. Assuming mₜ0ex0ex=0ex0ex175GeV and σ(pp̄→tt̄)0ex0ex=0ex0ex5.5pb, for M_H⁺0ex0ex=0ex0ex60GeV, we exclude tanβ<0.97 and tanβ>40.9.