Limits on t-quark decay into charged Higgs from a direct search at the CERN p$\overline{p}$ collider

Abstract A search for t-quark decay into charged Higgs, t→H + b, with the charged Higgs decaying via the H + → τ + v τ mode, has been done in proton-antiproton collisions at √2 = 0.63 TeV with the UA1 experiment. No evidence for this decay das been observed. Mass limits at 95% and 90% CL for the t-quark and the charged Higgs are presented. The results have also been interpreted in terms of the tan β parameter of a two-doublet Higgs sector.