809 research outputs found

    Measurements of top-quark pair differential cross-sections using the ATLAS detector at LHC

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    The measurements of cross-sections of the top-quark pair production provide an ideal way to perform stringent tests of the predictions of the perturbative Quantum Chromodynamics. In addition, they are sensitive to the parton distribution functions of the proton. This contribution shows the measurements in the semi-leptonic channel, using the data sample collected by the ATLAS experiment at the Large Hadron Collider during Run-2 at a centre-of-mass energy of 13 TeV, either by applying an inclusive selection or by using an exclusive selection as a function of the multiplicity of the hadronic jets. The measurements cover a wide kinematic region reaching the boosted regime, in which the values of the transverse momentum of the top quark are greater than 400 GeV. The results are compared with the most recent theoretical predictions

    High Prevalence of Arcobacter Carriage in Older Subjects with Type 2 Diabetes

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    Arcobacters are potential pathogens related to diarrheic infections and, rarely, septicaemia. This study evaluated the prevalence of arcobacters in stool samples of subjects with (n = 38) and without (n = 61) type 2 diabetes by using cultural and molecular techniques. Three Arcobacter positive cultures were found, all among diabetic subjects, whereas molecular analysis showed a carriage rate of 79% and 26.2% in subjects with and without type 2 diabetes (P < .001), respectively. The multivariate analysis showed that type 2 diabetes (β = 1.913; 95%CI: 2.378–19.285; P < .0001) and age (β = 1.744; 95%CI: 2.077–15.766; P = .001) were the only factors independently associated with arcobacters colonization in this population. Our study demonstrated a high prevalence of arcobacters colonization in type 2 diabetic and older subjects. The clinical significance and the potential health risk associated with these emerging species remain to be determined

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector