Search for charged Higgs bosons in decays of top quarks in proton - antiproton collisions at √s = 1.96 TeV

Abstract

In this dissertation we report on the first direct search for charged Higgs bosons in decays of top quarks in p$\bar{p}$ collisions at √s = 1.96 TeV. The search uses a data sample with an integrated luminosity of 2.2 fb-1 collected by the CDF II detector at Fermilab and looks for a resonance in the invariant mass distribution of two jets in the lepton+jets sample of t$\bar{t}$ candidates. We observe no evidence of charged Higgs bosons in top quark decays; hence 95% C.L. upper limits on the branching ratio are placed at β(t → H+b) < 0.1 to 0.3 for charged Higgs boson masses of 60 to 150 GeV/c2 assuming β(H+ → c$\bar{s}$) = 1.0 and β(t → Wb)+β(t → H+b) = 1.0. The upper limits on β(t → H+b) are also used as model independent limits on the decay branching ratio of top quarks to any charged scalar bosons beyond the standard model.