1,029 research outputs found

    Jet Physics at Tevatron

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    An overview of Run I jet physics at the ppbar Fermilab Tevatron Collider with a particular emphasis on inclusive jet cross section measurements is given. The impact of these studies on PDFs constrain from global fits is underlined. Preliminary results on inclusive jet and di-jet mass cross section measurements in Run II are then summarized.Comment: Presented at 15th Conference on High-Energy Physics (IFAE 2003), Lecce, Italy, 23-26 Apr 200

    QCD Physics at the Tevatron

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    Results on recent QCD measurements performed at the Tevatron ppbar Collider at sqrt{s} = 1.96 TeV are here reported. The inclusive jet and dijet mass cross sections are compared to NLO pQCD calculations and to Run I results. The production rates and kinematic properties of W + jets production processes are compared to ``enhanced'' LO theoretical predictions. Non-perturbative ``soft'' interactions leading to the underlying event are studied and compared to QCD Monte Carlo phenomenological models.Comment: Presented at 18th Les Rencontres De Physique De La Vallee D'Aoste: Results and Perspectives in Particle Physics, La Thuile, Aosta Valley, Italy, Feb. 29 - March 6, 200

    The TOTEM Experiment at LHC

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    The TOTEM experiment at the CERN LHC is here presented. After an overview of the experimental apparatus, the measurement of the total pp cross section, elastic scattering and diffractive phenomena is described. This physics programme will allow to distinguish among different models of soft proton interactionsComment: Presented at 22nd Les Rencontres de Physique de la Vallee d'Aoste, Aosta Valley, Italy, 24 Feb - 1 Mar 200

    Test of the two TOTEM TripleGEM Chambers assembled at G&A Engineering

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    In this note we report the results of the tests performed at CERN on the two TOTEM TripleGEM chambers assembled by a private company

    Echinococcosis — Rare Locations and Uncommon Clinical Manifestations

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    Echinococcosis is a zoonotic infection caused by tiny tapeworms of the genus Echinocococcus. Cystic Echinococcosis, also known as hydatid disease, is caused by Echinococcus granulosus and rarely by Echinococcus multilocularis

    Evidence for non-exponential elastic proton-proton differential cross-section at low |t| and sqrt(s) = 8 TeV by TOTEM

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    The TOTEM experiment has made a precise measurement of the elastic proton-proton differential cross-section at the centre-of-mass energy sqrt(s) = 8 TeV based on a high-statistics data sample obtained with the beta* = 90 optics. Both the statistical and systematic uncertainties remain below 1%, except for the t-independent contribution from the overall normalisation. This unprecedented precision allows to exclude a purely exponential differential cross-section in the range of four-momentum transfer squared 0.027 < |t| < 0.2 GeV^2 with a significance greater than 7 sigma. Two extended parametrisations, with quadratic and cubic polynomials in the exponent, are shown to be well compatible with the data. Using them for the differential cross-section extrapolation to t = 0, and further applying the optical theorem, yields total cross-section estimates of (101.5 +- 2.1) mb and (101.9 +- 2.1) mb, respectively, in agreement with previous TOTEM measurements.Comment: Final version published in Nuclear Physics

    Observation of Exclusive Gamma Gamma Production in p pbar Collisions at sqrt{s}=1.96 TeV

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    We have observed exclusive \gamma\gamma production in proton-antiproton collisions at \sqrt{s}=1.96 TeV, using data from 1.11 \pm 0.07 fb^{-1} integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E_T > 2.5 GeV and pseudorapidity |\eta| < 1.0, with no other particles detected in -7.4 < \eta < +7.4. The two showers have similar E_T and azimuthal angle separation \Delta\phi \sim \pi; 34 events have two charged particle tracks, consistent with the QED process p \bar{p} to p + e^+e^- + \bar{p} by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive \pi^0\pi^0 is consistent with zero and is < 15 at 95% C.L. The cross section for p\bar{p} to p+\gamma\gamma+\bar{p} with |\eta(\gamma)| < 1.0 and E_T(\gamma) > 2.5$ GeV is 2.48^{+0.40}_{-0.35}(stat)^{+0.40}_{-0.51}(syst) pb.Comment: 7 pages, 4 figure

    Search for heavy neutral lepton production in K+ decays

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    A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4| 2 and |UÎŒ4| 2 for heavy neutral lepton mass in the ranges 170–448 MeV/c2 and 250–373 MeV/c2, respectively. This improves on the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and above 300 MeV/c2 for |UÎŒ4|2