4,482 research outputs found

    Search for resonances in the dilepton mass distribution in pp collisions at √s = 7 TeV

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    A search for narrow resonances at high mass in the dimuon and dielectron channels has been performed by the CMS experiment at the CERN LHC, using pp collision data recorded at √s=7 TeV. The event samples correspond to integrated luminosities of 40 pb^(−1) in the dimuon channel and 35 pb^(−1) in the dielectron channel. Heavy dilepton resonances are predicted in theoretical models with extra gauge bosons (Zâ€Č) or as Kaluza-Klein graviton excitations (G_(KK)) in the Randall-Sundrum model. Upper limits on the inclusive cross section of Zâ€Č(G_(KK)) → ℓ^+ ℓ^− relative to Z → ℓ^+ ℓ^− are presented. These limits exclude at 95% confidence level a Zâ€Č with standard-model-like couplings below 1140GeV, the superstring-inspired Z'_ψ below 887 GeV, and, for values of the coupling parameter kM_(Pl) of 0.05 (0.1), Kaluza-Klein gravitons below 855 (1079) GeV

    Measurement of W^+W^− production and search for the Higgs boson in pp collisions at √s = 7 TeV

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    A measurement of W^+W^− production in pp collisions at √s = 7 TeV and a search for the Higgs boson are reported. The W^+W^− candidates are selected in events with two leptons, either electrons or muons. The measurement is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 36 pb^(−1). The pp → W^+W^− cross section is measured to be 41.1±15.3 (stat)±5.8(syst)±4.5(lumi)pb consistent with the standard model prediction. Limits on WWÎł and WWZ anomalous triple gauge couplings are set. The search for the standard model Higgs boson in the W^+W^− decay mode does not reveal any evidence of excess above backgrounds. Limits are set on the production of the Higgs boson in the context of the standard model and in the presence of a sequential fourth family of fermions with high masses. In the latter context, a Higgs boson with mass between 144 and 207 GeV/c^2 is ruled out at 95% confidence level
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