28 research outputs found

    Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV

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    Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s=7 TeV

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    Measurement of prompt J/ψ pair production in pp collisions at √s = 7 Tev

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    Study of hadronic event-shape variables in multijet final states in pp collisions at √s=7 TeV

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    Mechanical stability of the CMS strip tracker measured with a laser alignment system

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    Search for high-mass resonances in final states with a lepton and missing transverse momentum at root s=13 TeV

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    A search for new high-mass resonances in proton-proton collisions having final states with an electron or muon and missing transverse momentum is presented. The analysis uses proton-proton collision data collected in 2016 with the CMS detector at the LHC at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 35.9 fb(-1). The transverse mass distribution of the charged lepton-neutrino system is used as the discriminating variable. No significant deviation from the standard model prediction is found. The best limit, from the combination of electron and muon channels, is 5.2TeV at 95% confidence level for the mass of a W' boson with the same couplings as those of the standard model Wboson. Exclusion limits of 2.9TeV are set on the inverse radius of the extra dimension in the framework of split universal extra dimensions. In addition, model-independent limits are set on the production cross section and coupling strength of W' bosons decaying into this final state. An interpretation is also made in the context of an R parity violating supersymmetric model with a slepton as a mediator and flavor violating decay.Peer reviewe

    Observation of top quark pairs produced in association with a vector boson in pp collisions at s=8 √s=8TeV

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    Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb −1 , collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from t t ¯ W tt¯W or t t ¯ Z tt¯Z decays. The t t ¯ W tt¯W cross section is measured to be 382 − 102 + 117 fb with a significance of 4.8 standard deviations from the background-only hypothesis. The t t ¯ Z tt¯Z cross section is measured to be 242 − 55 + 65 fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the t t ¯ W tt¯W and t t ¯ Z tt¯Z cross sections

    Search for associated production of a Z boson with a single top quark and for tZ flavour-changing interactions in pp collisions at root s=8 TeV

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    A search for the production of a single top quark in association with a Z boson is presented, both to identify the expected standard model process and to search for flavour-changing neutral current interactions. The data sample corresponds to an integrated luminosity of 19.7 fb−1 recorded by the CMS experiment at the LHC in proton-proton collisions at s√=8s=8 TeV. Final states with three leptons (electrons or muons) and at least one jet are investigated. An events yield compatible with tZq standard model production is observed, and the corresponding cross section is measured to be σ(pp → tZq → ℓνbℓ+ℓ−q) = 10− 7+ 8 fb with a significance of 2.4 standard deviations. No presence of flavour-changing neutral current production of tZq is observed. Exclusion limits at 95% confidence level on the branching fractions of a top quark decaying to a Z boson and an up or a charm quark are found to be ℬ(t → Zu) < 0.022% and ℬ(t → Zc) < 0.049%
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