We present results of a direct search for charged Higgs production from[ital p][ital[anti p]] collisions at[radical]s= 1.8 TeV at Fermilab's Tevatron collider using the CDF detector. An expanded Higgs sector containing charged Higgs bosons is a persistent feature of candidate theories to replace the Standard Model. The minimal supersymmetric extension of the Standard Model, for example predicts that the dominant decay mode of the top quark is[ital t][r-arrow] H[sup+][ital b][r-arrow][tau][sup+][ital vb] for large values of tan[Beta]. We use the hadronic decays of the tau lepton in this channel to exclude charged Higgs bosons with M[sub H[sup[+-]]][lt] 140 GeV/c[sup 2] for large tan[Beta].
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 corresponding to 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% upper limits on the top quark decay branching ratio are placed at?(t → Hb)
We present the results on the searches for the SM and the MSSM Higgs boson production in proton-antiproton collisions at {radical}s = 1.96 GeV with the CDF detector. The Higgs bosons are searched for in various production and decay channels, with data samples corresponding to 400 pb{sup -1}. Using these measurements, we set an upper limit on the production cross section times branching fraction for the Standard Model Higgs as a function of the Higgs mass, and we obtain exclusion regions in the tan{beta} vs mass for the neutral MSSM Higgs, and branching fraction vs mass for the charged Higgs.
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 corresponding to 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% upper limits on the top quark decay branching ratio are placed at [Beta](t → H+b)
In this dissertation we report on the first direct search for charged Higgs bosons in decays of top quarks in p$ar{p}$ 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$ar{t}$ 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 ?(t → H+b) 0.1 to 0.3 for charged Higgs boson masses of 60 to 150 GeV/csup2/sup assuming ?(Hsup+/sup → c$ar{s}$) = 1.0 and ?(t → Wb)+?(t → Hsup+/supb) = 1.0. The upper limits on ?(t → Hsup+
Advanced analysis techniques together with increasing data samples are bringing the sensitivity of CDF to the Higgs boson very close to the SM predictions. These improvements translate into more stringent exclusions of parameter space in BSM Higgs sectors and of the SM mass range. The CDF Collaboration has a very active program on Higgs searches that comprises most accessible production mechanisms and decay channels in {bar p}p collisions at (square root)s = 1.96 TeV. This contribution will also review the combination of the different channels, data samples and analysis techinques that currently produces one of the most exciting experimental results in our field.
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 [Beta](t → H+b)
We present the results of the searches for new phenomena in pp collisions at √s=1.8 TeV with the CDF detector using the full data sample of 110 pb−1 collected between 1992 and 1995. We have searched for new physics in events with two photons, testing some of the hypotheses proposed to explain the appearance of the CDF ee[gamma][gamma] E{sub T} event. New results on the search for a heavy neutral scalar object, charged Higgs bosons (H{sup {+-}}) and the scalar top quark are presented. Finally we summarize the CDF results on the search for third generation leptoquarks.
The Standard Model predicts the existence of one neutral scalar Higgs boson, which is a remnant of the mechanism that breaks the SU(2)[sub L]xU(1)[sub Y] electroweak symmetry and generates masses for the heavy vector bosons and fermions. Many extensions to the Standard Model predict two or more Higgs doublets, resulting in a larger spectrum of Higgs bosons including a charged Higgs boson (H[sup [+-]]). For a light charged Higgs boson mass, the top decay into a charged Higgs boson and bottom quark might occur. This thesis presents results of a direct search for this top quark decay mode via the charged Higgs decay to a tau lepton and tau-neutrino, using the hadronic decays of the tau leptons. The search data consist of 100 pb[sup -1] of Run 1 data collected between 1992-1995 at the CDF detector, from p[anti p] collisions at a center-of-mass energy of 1.8 TeV produced at Fermilab's Tevatron accelerator. A total of seven events are observed in two search channels with an expected background contribution of 7.4[+-]2.0 events coming from fake taus (5.4[+-]1.5), heavy vector boson decays with jets (1.9[+-]1.3) and dibosons(0.08[+-]0.06). Lacking evidence for a signal, we set limits on charged Higgs production at the 95% confidence level in the charged Higgs mass plane versus tan[beta](a parameter of the theory) for a top quark mass of 175 GeV/c[sup 2] and for top production cross sections ([sigma][sub t[anti t]]) of 5.0 and 7.5 pb, assuming the Type-II Two-Higgs-Doublet-Model. For large tan[beta], this analysis excludes a charged Higgs boson of mass below 147(158)GeV/c[sup 2] for [sigma][sub t[anti t]]=5.0(7.5)pb. Using the Standard Model measured top quark cross section from CDF, this limit increases to 168 GeV/c[sup 2] and we also exclude a branching fraction of top decays via this charged Higgs mode of greater than 43% for charged Higgs masses below 168 GeV/c[sup 2].
