Search for charged Higgs bosons from top quark decays in $p\bar{p}$ collisions at $\sqrt{s} =$ 1.96-TeV.

We report the results of a search for a charged Higgs boson in the decays of top quarks produced in \ppbar collisions at a center-of-mass energy of 1.96 TeV. We use a data sample corresponding to an integrated luminosity of 193/pb collected by the upgraded Collider Detector at Fermilab. No evidence for charged Higgs production is found, allowing 95% C.L. upper limits to be placed on BR(t->H^+b) for different charged Higgs decay scenarios. In addition, we present in the MSSM (mH,tan beta) plane the first exclusion regions with radiative and Yukawa coupling corrections.