6,812 research outputs found

    Searches for a low-mass Higgs boson at the Tevatron

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    This proceeding presents an overview of recent experimental searches for the standard model Higgs boson. These searches are based on data collected by the CDF and the D0 experiments operating at the Fermilab Tevatron protonantiproton collider with √s = 1.96TeV. We focus on searches that are sensitive to a low-mass Higgs boson production with mH � 140GeV/c2. Using up to 4.2 fb−1 of data, both CDF and D0 find no evidence for Higgs boson production, and set 95% confidence level upper limits on Higgs boson production cross-section times branching ratio

    Search for the standard model Higgs boson in the H → ZZ → ℓ^+ℓ^−τ^+τ^− decay channel in pp collisions at √s = 7 TeV

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    A search is reported for the standard model Higgs boson in the H → ZZ → ℓ^+ℓ^−τ^+τ^− decay mode, where ℓ = μ or e, in proton-proton collisions at √s = 7TeV , corresponding to an integrated luminosity of 4.7 fb^(−1) collected with the CMS detector at the LHC. No evidence is found for a significant deviation from the background expectation. An upper limit four to twelve times larger than the predicted value is set at 95% confidence level for the product of the standard model Higgs boson production cross section and decay branching fraction in the mass range 190 < m_H < 600 GeV

    Tests of CMS hadron forward calorimeter upgrade readout box prototype

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    A readout box prototype for the CMS Hadron Forward calorimeter upgrade was built and tested in the CERN H2 beamline. The prototype was designed to enable simultaneous tests of different readout options for the four anode upgrade PMTs, new front-end electronics design and new cabling. The response of the PMTs with different readout options was uniform and the background response was minimal. Multi-channel readout options further enhanced the background elimination. Passing all the electronic, mechanical and physics tests, the readout box proved to be capable of providing the forward hadron calorimeter operational requirements in the upgrade era

    Search for SM Higgs Boson Produced in Association with a Z or a W Boson in events with / E T and b-jets

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    We present a search for the Standard Model Higgs boson produced in association with a Z or a W boson, using data collected with the CDF II detector at the Tevatron accelerator. A scenario where the Z decays into neutrinos or charged leptons originating from the W-decay escape detection and the Higgs decays into a bb pair is considered. Therefore the expected signature is large missing transverse energy ( E T ), no isolated leptons, and two b-jets. We present the preliminary results in this search using 1.7f b −1 of data collected by CDF and the work on future improvements to increase the sensitivity of the analysis

    Observation and studies of jet quenching in PbPb collisions at √sNN = 2.76 TeV

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    Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the Compact Muon Solenoid (CMS) detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 μb^(−1). Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cutoff used in this study (jet pT = 120 GeV/c) up to the statistical limit of the available data sample (jet pT ≈ 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet
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