3 research outputs found

    Evidence for electroweak production of W±W±jj in pp collisions at s√=8  TeV with the ATLAS detector

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    This Letter presents the first study of W±W±jj, same-electric-charge diboson production in association with two jets, using 20.3  fb−1 of proton-proton collision data at s√=8  TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with two reconstructed same-charge leptons (e±e±, e±μ±, and μ±μ±) and two or more jets are analyzed. Production cross sections are measured in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms. First evidence for W±W±jj production and electroweak-only W±W±jj production is observed with a significance of 4.5 and 3.6 standard deviations, respectively. The measured production cross sections are in agreement with standard model predictions. Limits at 95% confidence level are set on anomalous quartic gauge couplings

    Observation of Light-by-Light Scattering in Ultraperipheral Pb plus Pb Collisions with the ATLAS Detector

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    This letter describes the observation of the light-by-light scattering process, γγ→γγ\gamma\gamma\rightarrow\gamma\gamma, in Pb+Pb collisions at sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV. The analysis is conducted using a data sample corresponding to an integrated luminosity of 1.73 nb−1^{-1}, collected in November 2018 by the ATLAS experiment at the LHC. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy ETγ>3E_{\textrm{T}}^{\gamma} > 3 GeV and pseudorapidity ∣ηγ∣<2.37|\eta_{\gamma}| < 2.37, diphoton invariant mass above 6 GeV, and small diphoton transverse momentum and acoplanarity. After applying all selection criteria, 59 candidate events are observed for a background expectation of 12 ±\pm 3 events. The observed excess of events over the expected background has a significance of 8.2 standard deviations. The measured fiducial cross section is 78 ±\pm 13 (stat.) ±\pm 7 (syst.) ±\pm 3 (lumi.) nb.Comment: 29 pages in total, author list starting page 13, 2 figures, 0 tables, final version published in PRL. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2018-1

    Erratum: Search for Resonant and Nonresonant Higgs Boson Pair Production in the bb[over \uaf]\u3c4^+\u3c4^- Decay Channel in pp Collisions at sqrt[s]=13\u2009\u2009TeV with the ATLAS Detector [Phys. Rev. Lett. 121, 191801 (2018)]

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    This corrects the article DOI: 10.1103/PhysRevLett.121.191801
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