503 research outputs found

    Study of Diboson Production at CMS

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    I present an overview of the measurements of the di-boson (WW, WZ, ZZ, W\gamma, and Z\gamma) production cross sections in proton-proton collisions at \sqrt{s} = 7 TeV. The measurements are based on 36 pb^-1 and 1.1 fb^-1 of data collected with the CMS detector at the LHC in 2010 and 2011, respectively. The vector bosons W and Z are reconstructed in purely leptonic decays. The measured cross sections are compared with the Standard Model expectations calculated at next-to-leading order in perturbative QCD. Limits on anomalous triple gauge boson couplings are derived.Comment: 11 pages, 20 eps figures, 8 tables, proceedings of the Meeting of the Division of Particles and Fields of the American Physical Society, August 9-13, 2011, Brown University, Providence, Rhode Island, to be published electronically on the SLAC Electronic Proceedings repositor

    Isospin analysis of D0 decay to three pions

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    The final state of the decay D0 --> pi+ pi- pi0 is analyzed in terms of isospin eigenstates. It is shown that the final state is dominated by the isospin-0 component. This suggests that isospin considerations may provide insight into this and perhaps other \Dz-meson decay. We also discuss the isospin nature of the nonresonant contribution in the decay, which can be further understood by studying the decay D0 --> pi0 pi0 pi0.Comment: 10 pages, 2 postscript figures, submitted to Phys Rev

    Electroweak Corrections at High Energies

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    We present a survey of the most abundant processes at the LHC for sensitivity to electroweak corrections at \sqrt{s} = 8, 14, 33, and 100 TeV proton-proton collision energies. The processes studied are pp -> dijet, inclusive W and Z, W/Z+jets, and WW. In each case we compare the experimental uncertainty in the highest kinematic regions of interest with the relative magnitude of electroweak corrections and fixed-order \alpha_S calculations.Comment: Contribution to the Snowmass-2013 report of the QCD Working Group. 15 pages, 14 figures, 5 tables. Version 2: Added a new section 4A and updated the author list, acknowledgements, and references. Version 3: Added a new reference Ref.[36

    Differential cross section measurements for the production of a W boson in association with jets in proton‚Äďproton collisions at ‚ąös = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript ‚ąí1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

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