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{plus_minus}5.8 pb{sup {minus}1} of data recorded from p{ovr p} collisions at {radical}(s)=1.8 TeV by the D0 detector during 1992{endash}1996 at the Fermilab Tevatron. No evidence is found for charged Higgs production, and most parts of the [M{sub H{sup +}} {beta}] parameter space where the decay t{r_arrow}H{sup +}b has a branching fraction close to or larger than that for t{r_arrow}W{sup +}b are excluded at 95{percent} confidence level. Assuming m{sub t}=175 GeV and {sigma}(p{ovr p}{r_arrow} t{ovr t})=5.5 pb , for M{sub H{sup +}}=60 GeV , we exclude tan{number_sign}{beta}{lt}0.97 and tan{number_sign}{beta}{gt}40.9 . {copyright} {ital 1999} {ital The American Physical Society}