5 Search Results

A search for a Higgs boson with suppressed couplings to fermions, $$h_f$$, assumed to be the neutral, lower-mass partner of the Higgs boson discovered at the Large Hadron Collider, is reported. Such a Higgs boson could exist in extensions of the standard model with two Higgs doublets, and could be produced via $$p\bar{p} \to H^\pm h_f \to W^* h_f h_f \to 4\gamma + X$$, where $$H^\pm$$ is a charged Higgs boson. This analysis uses all events with at least three photons in the final state from proton-antiproton collisions at a center-of-mass energy of 1.96~TeV collected by the Collider Detector atmore » Fermilab, corresponding to an integrated luminosity of 9.2~$${\rm fb}^{-1}$$. No evidence of a signal is observed in the data. Values of Higgs-boson masses between 10 and 100 GeV/$c^2$ are excluded at 95\% Bayesian credibility.« less

Here, we describe a measurement of the ratio of the cross sections times branching fractions of the B_c⁺ meson in the decay mode B_c⁺ → J/ψμ⁺ν to the B⁺ meson in the decay mode B⁺ → J/ψK⁺ in proton-antiproton collisions at center-of-mass energy √s = 1.96 TeV. The measurement is based on the complete CDF Run II data set, which comes from an integrated luminosity of 8.7 fb^-1. The ratio of the production cross sections times branching fractions for B_c⁺ and B⁺ mesons with momentum transverse to the beam greater than 6 GeV/c and rapidity magnitude smaller than 0.6 ismore » 0.211 ± 0.012(stat)_-0.020^+0.021(syst). Using the known B⁺ → J/ψK⁺ branching fraction, the known B⁺ production cross section, and a selection of the predicted B_c⁺ → J/ψμ⁺ν branching fractions, the range for the total B_c⁺ production cross section is estimated.« less

In this study, we measure the forward--backward asymmetry of the production of top quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy $$\sqrt{s} = 1.96~\mathrm{TeV}$$ using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of $$9.1~\rm{fb}^{-1}$$. The asymmetry is characterized by the rapidity difference between top quarks and antiquarks ($$\Delta y$$), and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be $$A_{\text{FB}}^{t\bar{t}} = 0.12 \pm 0.13$$, consistentmore » with the expectations from the standard-model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive $$A_{\text{FB}}^{t\bar{t}}$$ in both final states yields $$A_{\text{FB}}^{t\bar{t}}=0.160\pm0.045$$, which is consistent with the SM predictions. We also measure the differential asymmetry as a function of $$\Delta y$$. A linear fit to $$A_{\text{FB}}^{t\bar{t}}(|\Delta y|)$$, assuming zero asymmetry at $$\Delta y=0$$, yields a slope of $$\alpha=0.14\pm0.15$$, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of $$A_{\text{FB}}^{t\bar{t}}(|\Delta y|)$$ in the two final states is $$\alpha=0.227\pm0.057$$, which is $$2.0\sigma$$ larger than the SM prediction.« less

In this study, we present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^-1 per experiment. The t-channel cross section is measured to be σ_t= 2.25$$+0.29\atop{-0.31}$$ pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_s+t= 3.30$$+0.52\atop{-0.40}$$ pb, without assuming the standard model value for the ratio σ_s/σ_t. The resulting valuemore » of the magnitude of the top-to-bottom quark coupling is |V_tb|= 1.02$$+0.06\atop{-0.05}$$, corresponding to |V_tb| > 0.92 at the 95% C.L.« less

We report a measurement of the indirect CP-violating asymmetries (A_Γ) between effective lifetimes of anticharm and charm mesons reconstructed in D⁰→K⁺K^- and D⁰→π⁺π^- decays. We use the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab experiment and corresponding to 9.7 fb^-1 of integrated luminosity. The strong-interaction decay D^*+→D⁰π⁺ is used to identify the meson at production as D⁰ or D^¯0. We statistically subtract D⁰ and D^¯0 mesons originating from b-hadron decays and measure the yield asymmetry between anticharm and charm decays as a function of decay time. We measure A_Γ(K⁺K^-)=(-0.19±0.15(stat)±0.04(syst))%and A_Γ(π⁺π^-)=(-0.01±0.18(stat)±0.03(syst))%. The results are consistentmore » with the hypothesis of CP symmetry and their combination yields A_Γ=(-0.12±0.12)%.« less