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    D0 Findings on the Top Quark

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    Recent results on top quark physics with the D0 experiment in pbar-p collisions at sqrt(s) = 1.8 TeV for an integrated luminosity of 125 pb**-1 are reported. The direct measurement of the top quark mass uses single lepton and dilepton events, giving the result m(top) = 172.1 +/- 7.1 GeV/c**2. The measurement of the t-tbar production cross section includes analyses from 9 top decay channels: dilepton (t-tbar --> e+mu, e+e, and mu+mu), electron and neutrino (t-tbar --> e+nu), single leptons (t-tbar --> e + jets, t-tbar --> mu + jets) with and without b tagging, and all-jets (t-tbar --> 6 jets). We measure the t-tbar production cross section to be 5.9 +/- 1.7 pb at m(top) = 172.1 GeV/c**2. Combining the D0 and the CDF measurements of the top quark mass and combining their t-tbar cross sections, in both cases taking into account error correlations, yields unofficially sigma(t-tbar) = 6.7 +/- 1.3 pb at an averaged top quark mass of m(top) = 173.8 +/- 5.2 GeV/c**2. Preliminary results on a search for charged Higgs production in top events, t --> Higgs + b, are presented.Comment: 21 pages, 10 figures, 1 tabl

    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

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