1,745 research outputs found

    Differential ttňČt\bar{t} Cross Section Measurements as a Function of Variables other than Kinematics

    Full text link
    An overview of cross section measurements as a function of jet multiplicities and jet kinematics in association with ttňČt\bar{t} production is presented. Both the ATLAS and the CMS collaborations performed a large number of measurements at different center-of-mass energies of the LHC using various ttňČt\bar{t} decay channels. Theoretical predictions of these quantities usually rely on parton shower simulations that strongly depends on tunable parameters and come with large uncertainties. The measurements are compared to various theoretical descriptions based on different combinations of matrix-element calculations and parton-shower models

    Measurements of differential ttňČt\bar{t} production cross sections at CMS

    Full text link
    An overview of recent measurements of differential top quark pair production cross sections performed by the CMS experiment at the LHC is presented. Measurements at different proton-proton center-of-mass energies are available using the dilepton, lepton+jets, and all-jets decay channels of the top quark. In addition to the measurements of parton-level top quarks, many measurements at particle level in an experimental accessible phase space are now available. For these results the dependence on theoretical extrapolations is reduced. A common observation of all measurements is a softer transverse momentum of the top quark than predicted by state of the art standard model calculations. However, new calculations with NNLO QCD and NLO electro-weak precision show an improved agreement

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

    Get PDF
    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

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an