16 research outputs found

    Search for Kaluza-Klein Graviton Emission in ppˉp\bar{p} Collisions at s=1.8\sqrt{s}=1.8 TeV using the Missing Energy Signature

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    We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb1{pb}^{-1} of \ppb collisions at s\sqrt{s} = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a 3+1+n3+1+n-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for nn=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure

    Measurement of the average time-integrated mixing probability of b-flavored hadrons produced at the Tevatron

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    We have measured the number of like-sign (LS) and opposite-sign (OS) lepton pairs arising from double semileptonic decays of bb and bˉ\bar{b}-hadrons, pair-produced at the Fermilab Tevatron collider. The data samples were collected with the Collider Detector at Fermilab (CDF) during the 1992-1995 collider run by triggering on the existence of μμ\mu \mu and eμe \mu candidates in an event. The observed ratio of LS to OS dileptons leads to a measurement of the average time-integrated mixing probability of all produced bb-flavored hadrons which decay weakly, χˉ=0.152±0.007\bar{\chi} = 0.152 \pm 0.007 (stat.) ±0.011\pm 0.011 (syst.), that is significantly larger than the world average χˉ=0.118±0.005\bar{\chi} = 0.118 \pm 0.005.Comment: 47 pages, 10 figures, 15 tables Submitted to Phys. Rev.

    Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV

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    We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with next-to-leading order (NLO) quantum chromodynamics (QCD)

    MEASUREMENT OF THE BETA-MESON AND B-QUARK CROSS-SECTIONS AT ROOT-S = 1.8 TEV USING THE EXCLUSIVE DECAY BETA+/--]J/PSI-KAPPA+/-

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    This Letter reports the full reconstruction of B mesons through the decay chain B +/- --> J/psi-K +/-, J/psi --> mu+-mu-, using data obtained at thc Collider Detector at Fermilab in ppBAR collisions at square-root s = 1.8 TeV. This exclusive sample, the first observed at a hadron collider, is then used to measure the B-meson cross section, from which we extract the b-quark cross section. We obtain sigma = 2.8 +/- 0.9(stat) +/- 1.1 (syst) mu-b for B- mesons with P(T) > 9.0 GeV/c and rapidity \y\ 11.5 GeV/c and rapidity \y\ < 1.0

    MEASUREMENT OF THE ISOLATED PROMPT PHOTON CROSS-SECTION IN (P)BAR-P COLLISIONS AT ROOT-S = 1.8 TEV

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    We present a measurement of the cross section for production of isolated prompt photons in ppBAR collisions at square-root s = 1.8 TeV. The cross section, measured as a function of transverse momentum (P(T)), agrees qualitatively with QCD calculations but has a steeper slope at low P(T)

    INCLUSIVE JET CROSS-SECTION IN PBARP COLLISIONS AT SQUARE-ROOT-S = 1.8 TEV

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    We present a measurement of the inclusive jet cross section in ppBAR collisions at square-root s = 1.8 TeV at the Fermilab Tevatron using the Collider Detector at Fermilab. Good agreement is seen with the predictions of recent next-to-leading-order [O(alpha(s)3)] QCD predictions. The dependence of the cross section on clustering cone size is reported for the first time. An improved limit on LAMBDA(c), a term characterizing possible quark substructure, is set at 1.4 TeV (95% C.L.)

    MEASUREMENT OF JET SHAPES IN (P)OVER-BAR-P COLLISIONS AT ROOT-S = 1.8 TEV

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    We present a measurement of jet shapes in ppBAR collisions at square-root s = 1.8 TeV at the Fermilab Tevatron using the Collider Detector at Fermilab (CDF). Qualitative agreement is seen with the predictions of recent next-to-leading [O(alpha(s)3)] calculations and with leading logarithm QCD based Monte Carlo simulations. The dependence of the jet shape on transverse energy is studied

    Search for pair production of scalar top quarks in R-parity violating decay modes in p(p)over-bar collisions at root s=1.8 TeV

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    The search for pair production of scalar top quarks in an R-parity violating supersymmetry scenario in 106 pb-f of pp̄ collisions at √s = 1.8 TeV collected by the Collider Detector at Fermilab was discussed. It was found that in this mode each t1̃ decayed into a τ lepton and a b quark. The events with two τ's, one decaying leptonically and one decaying hadronically and two jets were searched. It was observed that a 95% confidence level lower limit was set on the t 1̄ mass at 122 GeV/c2 for Br(t1̃ → τb)
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