4 research outputs found

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

    Get PDF
    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

    Measurement of the underlying event activity using charged-particle jets in proton-proton collisions at <tex>\sqrt{s}$</tex>=2.76 TeV

    No full text

    Measurement of the underlying event activity using charged-particle jets in proton-proton collisions at 2.76 TeV

    Get PDF
    see paper for full list of authorsInternational audienceA measurement of the underlying event (UE) activity in proton-proton collisions is performed using events with charged-particle jets produced in the central pseudorapidity region (abs(eta[jet]) 0.5 GeV, in the azimuthal region transverse to the highest pt jet direction. By further dividing the transverse region into two regions of smaller and larger activity, various components of the UE activity are separated. The measurements are compared to previous results at 0.9 and 7 TeV, and to predictions of several Monte Carlo event generators, providing constraints on the modelling of the UE dynamics

    Search for supersymmetry in the vector-boson fusion topology in proton-proton collisions at <tex>\sqrt{s}$</tex>=8TeV

    No full text
    corecore