1,106 research outputs found

    Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

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    In the version of this article initially published, the ATLAS Collaboration author names, affiliations and acknowledgements were omitted and have now been included in the HTML and PDF versions of the article

    Measurements of azimuthal anisotropies of jet production in Pb+Pb collisions at √sNN = 5.02 TeV with the ATLAS detector

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    The azimuthal variation of jet yields in heavy-ion collisions provides information about the path-length dependence of the energy loss experienced by partons passing through the hot, dense nuclear matter known as the quark–gluon plasma. This paper presents the azimuthal anisotropy coefficients v 2 , v 3 , and v 4 measured for jets in Pb + Pb collisions at √ s NN = 5.02 TeV using the ATLAS detector at the LHC. The measurement uses data collected in 2015 and 2018, corresponding to an integrated luminosity of 2.2 nb − 1 . The v n values are measured as a function of the transverse momentum of the jets between 71 and 398 GeV and the event centrality. A nonzero value of v 2 is observed in all but the most central collisions. The value of v 2 is largest for jets with lower transverse momentum, with values up to 0.05 in mid-central collisions. A smaller, nonzero value of v 3 of approximately 0.01 is measured with no significant dependence on jet p T or centrality, suggesting that fluctuations in the initial state play a small but distinct role in jet energy loss. No significant deviation of v 4 from zero is observed in the measured kinematic region

    Search for Dark Matter Produced in Association with a Dark Higgs Boson Decaying into W^{±}W^{∓} or ZZ in Fully Hadronic Final States from sqrt[s]=13  TeV pp Collisions Recorded with the ATLAS Detector.

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    Several extensions of the Standard Model predict the production of dark matter particles at the LHC. An uncharted signature of dark matter particles produced in association with VV=W^{±}W^{∓} or ZZ pairs from a decay of a dark Higgs boson s is searched for using 139  fb^{-1} of pp collisions recorded by the ATLAS detector at a center-of-mass energy of 13 TeV. The s→V(qq[over ¯])V(qq[over ¯]) decays are reconstructed with a novel technique aimed at resolving the dense topology from boosted VV pairs using jets in the calorimeter and tracking information. Dark Higgs scenarios with m_{s}>160  GeV are excluded

    Search for a new heavy scalar particle decaying into a Higgs boson and a new scalar singlet in final states with one or two light leptons and a pair of τ-leptons with the ATLAS detector

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    A search for a new heavy scalar particle X decaying into a Standard Model (SM) Higgs boson and a new singlet scalar particle S is presented. The search uses a proton-proton (pp) collision data sample with an integrated luminosity of 140 fb−1 recorded at a centre-of-mass energy of √s = 13 TeV with the ATLAS detector at the Large Hadron Collider. The most sensitive mass parameter space is explored in X mass ranging from 500 to 1500 GeV, with the corresponding S mass in the range 200–500 GeV. The search selects events with two hadronically decaying τ-lepton candidates from H → τ+τ− decays and one or two light leptons (ℓ = e, μ) from S → VV (V = W, Z) decays while the remaining V boson decays hadronically or to neutrinos. A multivariate discriminant based on event kinematics is used to separate the signal from the background. No excess is observed beyond the expected SM background and 95% confidence level upper limits between 72 fb and 542 fb are derived on the cross-section σ(pp → X → SH) assuming the same SM-Higgs boson-like decay branching ratios for the S → VV decay. Upper limits on the visible cross-sections σ(pp → X → SH → WWττ) and σ(pp → X → SH → ZZττ) are also set in the ranges 3–26 fb and 6–33 fb, respectively

    Search for non-resonant Higgs boson pair production in final states with leptons, taus, and photons in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search is presented for non-resonant Higgs boson pair production, targeting the bbZZ, 4V (V = W or Z), V V τ τ , 4τ , γγV V and γγτ τ decay channels. Events are categorised based on the multiplicity of light charged leptons (electrons or muons), hadronically decaying tau leptons, and photons. The search is based on a data sample of proton-proton collisions at √s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb−1 . No evidence of the signal is found and the observed (expected) upper limit on the cross-section for non-resonant Higgs boson pair production is determined to be 17 (11) times the Standard Model predicted cross-section at 95% confdence level under the background-only hypothesis. The observed (expected) constraints on the HHH coupling modifer, κλ, are determined to be −6.2 < κλ < 11.6 (−4.5 < κλ < 9.6) at 95% confdence level, assuming the Standard Model for the expected limits and that new physics would only afect κλ

    Study of high-transverse-momentum Higgs boson production in association with a vector boson in the qqbb final state with the ATLAS detector

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    This Letter presents the first study of Higgs boson production in association with a vector boson ( V = W or Z ) in the fully hadronic q q b b final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at √ s = 13     TeV and corresponding to an integrated luminosity of 137     fb − 1 . The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b -tagging properties are used to identify jets consistent with Higgs bosons decaying into b ¯ b . Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The V H production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250–450, 450–650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ = 1.4 + 1.0 − 0.9 and the corresponding cross section is 3.1 ± 1.3 ( stat ) + 1.8 − 1.4 ( syst )     pb

    A search for an unexpected asymmetry in the production of e+μe^+ \mu^- and eμ+e^- \mu^+ pairs in proton-proton collisions recorded by the ATLAS detector at s=13\sqrt s = 13 TeV

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    This search, a type not previously performed at ATLAS, uses a comparison of the production cross sections for e+μe^+ \mu^- and eμ+e^- \mu^+ pairs to constrain physics processes beyond the Standard Model. It uses 139fb1139 \text{fb}^{-1} of proton-proton collision data recorded at s=13\sqrt{s} = 13 TeV at the LHC. Targeting sources of new physics which prefer final states containing e+μe^{+}\mu^{-} to eμ+e^{-}\mu^{+}, the search contains two broad signal regions which are used to provide model-independent constraints on the ratio of cross sections at the 2% level. The search also has two special selections targeting supersymmetric models and leptoquark signatures. Observations using one of these selections are able to exclude, at 95% confidence level, singly produced smuons with masses up to 640 GeV in a model in which the only other light sparticle is a neutralino when the RR-parity-violating coupling λ231\lambda'_{231} is close to unity. Observations using the other selection exclude scalar leptoquarks with masses below 1880 GeV when g1Reu=g1Rμc=1g_{\text{1R}}^{eu}=g_{\text{1R}}^{\mu c}=1, at 95% confidence level. The limit on the coupling reduces to g1Reu=g1Rμc=0.46g_{\text{1R}}^{eu}=g_{\text{1R}}^{\mu c}=0.46 for a mass of 1420 GeV.Comment: 38 pages in total, author list starting page 22, 8 figures, 1 table, submitted to Physics Letters B. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2018-29

    Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector

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    This Letter presents the first study of Higgs boson production in association with a vector boson (V 1⁄4 W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at √s = 13 TeV and corresponding to an integrated luminosity of 137 fb−1. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb̄. Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The VH production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250–450, 450–650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ = 1.4+1.0−0.9 and the corresponding cross section is 3.1 ± 1.3(stat)+1.8−1.4(syst) pb

    Search for Higgs boson pair production in association with a vector boson in pp collisions at √s=13TeV with the ATLAS detector

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    This paper reports a search for Higgs boson pair (hh) production in association with a vector boson (W or Z) using 139 fb−1 of proton–proton collision data at √s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The search is performed in final states in which the vector boson decays leptonically (W → ν, Z → , νν with = e, μ) and the Higgs bosons each decay into a pair of b-quarks. It targets Vhh signals from both non-resonant hh production, present in the Standard Model (SM), and resonant hh production, as predicted in some SM extensions. A 95% confidence-level upper limit of 183 (87) times the SM cross-section is observed (expected) for non-resonant V hh production when assuming the kinematics are as expected in the SM. Constraints are also placed on Higgs boson coupling modifiers. For the resonant search, upper limits on the production cross-sections are derived for two specific models: one is the production of a vector boson along with a neutral heavy scalar resonance H, in the mass range 260–1000 GeV, that decays into hh, and the other is the production of a heavier neutral pseudoscalar resonance A that decays into a Z boson and H boson, where the A boson mass is 360–800 GeV and the H boson mass is 260– 400 GeV. Constraints are also derived in the parameter space of two-Higgs-doublet models

    Dor e analgesia pós-operatórias no Hospital Infantil Joana de Gusmão.

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    Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Departamento de Pediatria, Curso de Medicina, Florianópolis, 200
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