60 research outputs found

    Inclusive jet cross section in pˉp{\bar p p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    The inclusive jet differential cross section has been measured for jet transverse energies, ETE_T, from 15 to 440 GeV, in the pseudorapidity region 0.1η\leq | \eta| \leq 0.7. The results are based on 19.5 pb1^{-1} of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with ET>200E_T>200 GeV is significantly higher than current predictions based on O(αs3\alpha_s^3) perturbative QCD calculations. Various possible explanations for the high-ETE_T excess are discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review Letter

    Search for charged Higgs decays of the top quark using hadronic tau decays

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    We present the result of a search for charged Higgs decays of the top quark, produced in ppˉp\bar{p} collisions at s=\surd s = 1.8 TeV. When the charged Higgs 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 the period 1992-1993 at the Collider Detector at Fermilab, corresponding to 18.7±\pm0.7~pb1^{-1}, exclude new regions of combined top quark and charged Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp; submitted to Phys. Rev.

    The Charge Asymmetry in W-Boson Decays Produced in p-pbar Collisions at sqrt(s) = 1.8 TeV

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    The charge asymmetry has been measured using 19,039 W19,039~W decays recorded by the CDF detector during the 1992-93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio of dd and uu quark distributions to x<0.01x<0.01 at Q2MW2Q^2 \approx M_W^2, where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts and Stirling (MRS) are favored over the sets most recently produced by the CTEQ collaboration. The WW asymmetry data provide a stronger constraints on d/ud/u ratio than the recent measurements of F2μn/F2μpF_2^{\mu n}/F_2^{\mu p} which are limited by uncertainties originating from deutron corrections.Comment: to be published in PR

    Search for New Particles Decaying to Dijets in p-pbar Collisions at sqrt(s)=1.8 TeV

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    We have used 19 pb**-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at 95% confidence level models containing the following new particles: axigluons with mass between 200 and 870 GeV, excited quarks with mass between 80 and 570 GeV, and color octet technirhos with mass between 320 and 480 GeV.Comment: Submitted to Physical Review Letters in December 199

    Measurement of σB(Weν)\sigma \cdot B (W \to e \nu) and σB(Z0e+e)\sigma \cdot B(Z^0 \to e^+e^-) in ppˉp {\bar p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    We present a measurement of σB(Weν)\sigma \cdot B(W \to e \nu) and σB(Z0e+e)\sigma \cdot B(Z^0 \to e^+e^-) in proton - antiproton collisions at s=1.8\sqrt{s} =1.8 TeV using a significantly improved understanding of the integrated luminosity. The data represent an integrated luminosity of 19.7 pb1^{-1} from the 1992-1993 run with the Collider Detector at Fermilab (CDF). We find σB(Weν)=2.49±0.12\sigma \cdot B(W \to e \nu) = 2.49 \pm 0.12~nb and σB(Z0e+e)=0.231±0.012\sigma \cdot B(Z^0 \to e^+e^-) = 0.231 \pm 0.012~nb.Comment: Uses Latex, Article 12 point, figure appended as uuencoded file The full PostScript available via WWW at http://www-cdf.fnal.gov/physics/pub95/cdf3312_sigma_1a_prl_v3.p

    Measurement of correlated μoverlineb\mu - {overline b} jet cross sections in ppˉp {\bar p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    We report on measurements of differential μbˉ\mu - {\bar b} cross sections, where the muon is from a semi-leptonic bb decay and the bˉ{\bar b} is identified using precision track reconstruction in jets. The semi-differential correlated cross sections, dσ\sigma/d\Et^{{\bar b}}, dσ\sigma/d\pt^{{\bar b}}, and dσ\sigma/dδϕ(μbˉ)\delta\phi(\mu - {\bar b}) for \pt^{\mu}>~9 GeV/c, ημ|\eta^{\mu}|~10 GeV, ηbˉ<|\eta^{{\bar b}}|<~1.5, are presented and compared to next-to-leading order QCD calculations.Comment: Uses Latex, Article 12 point, figures appended as uuencoded file The full PostScript available via WWW at http://www-cdf.fnal.gov/physics/pub95/cdf3164_mu_bbar_prd_final.p

    Limits on WWZWWZ and WWγWW\gamma couplings from WWWW and WZWZ production in ppp\overline{p} collisions at s=1.8\sqrt{s} = 1.8 TeV

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    Direct limits are set on WWZWWZ and WWγWW\gamma three-boson couplings in a search for WWWW and WZWZ production with high transverse momentum in ppp\overline{p} collisions at s=1.8\sqrt{s} = 1.8 TeV, using the Collider Detector at Fermilab. The results are in agreement with the SU(2) ×\times U(1) model of electroweak interactions. Assuming Standard Model WWγWW\gamma coupling, the the limits are interpreted as direct evidence for a non-zero WWZWWZ coupling at subprocess energies near 500 GeV. Alternatively, assumiong identical WWZWWZ and WWγWW\gamma couplings, bounds 0.11<κ<2.27-0.11 < \kappa < 2.27 and 0.81<λ<0.84-0.81 < \lambda < 0.84 are obtained at 95%95\% CL for a form factor scale 1000 GeV.Comment: 16 pages, submitted to PRL, URL: http://www-cdf.fnal.gov/physics/pub95/cdf2951_vvprl.p

    Measurement of the BB Meson Differential Cross Section, dσ/dpTd\sigma/dp_T, in ppˉp\bar{p} Collisions at s=1.8\sqrt{s} = 1.8 TeV

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    This paper presents the first direct measurement of the BB meson differential cross section, dσ/dpTd\sigma/dp_T, in ppˉp\bar{p} collisions at s=1.8\sqrt{s}=1.8 TeV using a sample of 19.3±0.719.3 \pm 0.7 pb1^{-1} accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region y6.0|y| 6.0 GeV/cc by fully reconstructing the BB meson decays B+J/ψK+B^{+}\to J/\psi K^{+} and B0J/ψK0(892)B^{0}\to J/\psi K^{*0}(892), where J/ψμ+μJ/\psi \to \mu^+\mu^- and K0K+πK^{*0} \to K^+ \pi^-. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.Comment: 14 pages. Submitted to Phys. Rev. Lett. The postscript file is at http://www-cdf.fnal.gov/physics/pub95/cdf2893_bexcl_xsection.p

    Study of ttbar Production in ppbar Collisions Using Total Transverse Energy

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    We analyze a sample of W + jet events collected with the Collider Detector at Fermilab (CDF) in ppbar collisions at sqrt(s) = 1.8 TeV to study ttbar production. We employ a simple kinematical variable "H", defined as the scalar sum of the transverse energies of the lepton, neutrino and jets. For events with a W boson and four or more jets, the shape of the "H" distribution deviates by 3.8 standard deviations from that expected from known backgrounds to ttbar production. However this distribution agrees well with a linear combination of background and ttbar events, the agreement being best for a top mass of 180 GeV/c^2.Comment: Postscript file (gzip+uuencode). 5-page, two-column PRL format (RevTex). Submitted to Phys. Rev. Lett. 09 June 199

    Search For 2nd-generation Leptoquarks In P(p)over-bar Collisions At Root-s=1.8 Tev

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    We present the results of a search for second generation leptoquarks S-2 using 19.3 pb(-1) of data collected at the Collider Detector at Fermilab (CDF) in p (p) over bar collisions at root s = 1.8 TeV during the 1992-93 collider run. We have searched for S-2 (S) over bar(2) pairs assuming that each leptoquark decays to a muon + quark with a branching ratio beta. We find two candidate events, consistent with an expected background of 1.11 +/- 0.48. We obtain upper limits on sigma(pp --> S-2 (S) over bar(2))beta(2) as a function of M(S2). Using a Monte Carlo prediction for S-2 (S) over bar(2) pair production, we exclude M(S2) < 131 GeV/c(2) for beta = 1 and M(S2) < 95 GeV/c(2) for beta = 0.5 at 95% C.L
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