169 research outputs found

    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 σ⋅B(W→eÎœ)\sigma \cdot B (W \to e \nu) and σ⋅B(Z0→e+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 σ⋅B(W→eÎœ)\sigma \cdot B(W \to e \nu) and σ⋅B(Z0→e+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 pb−1^{-1} from the 1992-1993 run with the Collider Detector at Fermilab (CDF). We find σ⋅B(W→eÎœ)=2.49±0.12\sigma \cdot B(W \to e \nu) = 2.49 \pm 0.12~nb and σ⋅B(Z0→e+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 Ό−overlineb\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 Ό−bˉ\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/dÎŽÏ•(Ό−bˉ)\delta\phi(\mu - {\bar b}) for \pt^{\mu}>~9 GeV/c, âˆŁÎ·ÎŒâˆŁ|\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

    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 pb−1^{-1} accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region ∣y∣6.0|y| 6.0 GeV/cc by fully reconstructing the BB meson decays B+→J/ψK+B^{+}\to J/\psi K^{+} and B0→J/ψK∗0(892)B^{0}\to J/\psi K^{*0}(892), where J/ψ→Ό+Ό−J/\psi \to \mu^+\mu^- and K∗0→K+π−K^{*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

    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 Q2≈MW2Q^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 F2ÎŒn/F2ÎŒpF_2^{\mu n}/F_2^{\mu p} which are limited by uncertainties originating from deutron corrections.Comment: to be published in PR

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

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    Direct limits are set on WWZWWZ and WWÎłWW\gamma three-boson couplings in a search for WWWW and WZWZ production with high transverse momentum in pp‟p\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 WWÎłWW\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 WWÎłWW\gamma couplings, bounds −0.11<Îș<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

    Jet-fragmentation Properties In Pbarp Collisions At Square-root-s = 1.8 Tev

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    2-jet Invariant-mass Distribution At Square-root-s = 1.8-tev

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    We present the dijet invariant-mass distribution in the region between 60 and 500 GeV, measured in 1.8-TeV p»p collisions in the Collider Detector at Fermilab. Jets are restricted to the pseudorapidity interval ||&lt;0.7. Data are compared with QCD calculations; axigluons are excluded with 95% confidence in the region 120
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