We present the result of a search for charged Higgs boson decays of the top quark, produced in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}$ TeV. When the charged Higgs boson is heavy and decays to a $\tau$ lepton, which subsequently decays hadronically, the resulting events have a unique signature: large missing transverse energy and the low-charged-multiplicity $\tau$. Data collected in 1992 and 1993 at the Collider Detector at Fermilab, corresponding to 18.7±0.7 ${\mathrm{pb}}^{-1\mathrm{}}$, exclude new regions of combined top quark and charged Higgs boson mass, in extensions to the standard model with two Higgs doublets.

• Received 10 January 1996

DOI:https://doi.org/10.1103/PhysRevD.54.735