449 research outputs found

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    X-ray Nanodiffraction on a Single SiGe Quantum Dot inside a Functioning Field-Effect Transistor

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    For advanced electronic, optoelectronic, or mechanical nanoscale devices a detailed understanding of their structural properties and in particular the strain state within their active region is of utmost importance. We demonstrate that X-ray nanodiffraction represents an excellent tool to investigate the internal structure of such devices in a nondestructive way by using a focused synchotron X-ray beam with a diameter of 400 nm. We show results on the strain fields in and around a single SiGe island, which serves as stressor for the Si-channel in a fully functioning Si-metal-oxide semiconductor field-effect transistor

    Sindicalismo docente e política educacional: tensões e composições de interesses corporativos e qualidade da educação

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    O Sindicalismo docente brasileiro tem suas raízes em antigos movimentos ao redor da construção de um Sistema Público de Ensino no país. Desde o movimento dos pioneiros, passando pela LDB de 1946, pelos debates ao redor do capítulo de educação na Constituinte de 1988 e a LDB de 1996; as reivindicações de base corporativa dos professores estiveram estruturalmente vinculadas aos conflitos sobre as condições de oferta do ensino público e sua incidência na qualidade da educação. Com o novo quadro institucional, resultante da Constituição de 1988, que legalizou a representação sindical docente e, numa perspectiva participativa, abriu um amplo leque de Conselhos, que se tornaram novos espaços de ação sindical, justifica-se a necessidade de estudos comparativos entre casos locais. Este trabalho, a partir de uma base empírica que se apoia em entrevistas com dirigentes dos sindicatos de trabalhadores em educação das cidades de Curitiba, Fazenda Rio Grande, Araucária e Piraquara, no Paraná, e Dourados, no Mato Grosso do Sul, analisa a ação sindical docente nos últimos 15 anos, explicitando como se articulam interesses corporativo-trabalhistas e política educacional, sob a ótica dos Sindicatos

    The CMS High Level Trigger

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    At the Large Hadron Collider at CERN the proton bunches cross at a rate of 40MHz. At the Compact Muon Solenoid experiment the original collision rate is reduced by a factor of O (1000) using a Level-1 hardware trigger. A subsequent factor of O(1000) data reduction is obtained by a software-implemented High Level Trigger (HLT) selection that is executed on a multi-processor farm. In this review we present in detail prototype CMS HLT physics selection algorithms, expected trigger rates and trigger performance in terms of both physics efficiency and timing.Comment: accepted by EPJ Nov 200

    Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

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    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Measurement of the triple-differential cross section for photon plus jets production in proton-proton collisions at √s = 7 TeV

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    Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at √s=8 TeV

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    Measurement of the prompt J/psi and psi(2S) polarizations in pp collisions at sqrt(s) = 7 TeV

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    The polarizations of prompt J/psi and psi(2S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 inverse femtobarns. The prompt J/psi and psi(2S) polarization parameters lambda[theta], lambda[phi], and lambda[theta, phi], as well as the frame-invariant quantity lambda(tilde), are measured from the dimuon decay angular distributions in three different polarization frames. The J/psi results are obtained in the transverse momentum range 14 < pt < 70 GeV, in the rapidity intervals abs(y) < 0.6 and 0.6 < abs(y) < 1.2. The corresponding psi(2S) results cover 14 < pt < 50 GeV and include a third rapidity bin, 1.2 < abs(y) < 1.5. No evidence of large transverse or longitudinal polarizations is seen in these kinematic regions, which extend much beyond those previously explored
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