120 research outputs found

    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

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    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

    Boronic acids for sensing and other applications - a mini-review of papers published in 2013

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    Boronic acids are increasingly utilised in diverse areas of research. Including the interactions of boronic acids with diols and strong Lewis bases as fluoride or cyanide anions, which leads to their utility in various sensing applications. The sensing applications can be homogeneous assays or heterogeneous detection. Detection can be at the interface of the sensing material or within the bulk sample. Furthermore, the key interaction of boronic acids with diols allows utilisation in various areas ranging from biological labelling, protein manipulation and modification, separation and the development of therapeutics. All the above uses and applications are covered by this mini-review of papers published during 2013

    Accuracy versus precision in boosted top tagging with the ATLAS detector

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    Abstract The identification of top quark decays where the top quark has a large momentum transverse to the beam axis, known as top tagging, is a crucial component in many measurements of Standard Model processes and searches for beyond the Standard Model physics at the Large Hadron Collider. Machine learning techniques have improved the performance of top tagging algorithms, but the size of the systematic uncertainties for all proposed algorithms has not been systematically studied. This paper presents the performance of several machine learning based top tagging algorithms on a dataset constructed from simulated proton-proton collision events measured with the ATLAS detector at √ s = 13 TeV. The systematic uncertainties associated with these algorithms are estimated through an approximate procedure that is not meant to be used in a physics analysis, but is appropriate for the level of precision required for this study. The most performant algorithms are found to have the largest uncertainties, motivating the development of methods to reduce these uncertainties without compromising performance. To enable such efforts in the wider scientific community, the datasets used in this paper are made publicly available.</jats:p

    Combined measurement of the Higgs boson mass from the H → γγ and H → ZZ∗ → 4ℓ decay channels with the ATLAS detector using √s = 7, 8, and 13 TeV pp collision data

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    A measurement of the mass of the Higgs boson combining the H → Z Z ∗ → 4 ℓ and H → γ γ decay channels is presented. The result is based on 140     fb − 1 of proton-proton collision data collected by the ATLAS detector during LHC run 2 at a center-of-mass energy of 13 TeV combined with the run 1 ATLAS mass measurement, performed at center-of-mass energies of 7 and 8 TeV, yielding a Higgs boson mass of 125.11 ± 0.09 ( stat ) ± 0.06 ( syst ) = 125.11 ± 0.11     GeV . This corresponds to a 0.09% precision achieved on this fundamental parameter of the Standard Model of particle physics

    Polymer supported calix[4]arene-semicarbazone derivative for separation and preconcentration of La(III), Ce(III), Th(IV) and U(VI)

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    The new "upper-rim" functionalized 11,23-disemicarbazono-26,28-n-dipropoxy-25,27-dihydroxy calix[4]arene has been synthesized by condensing 11,23-diformyl-26,28-n-dipropoxy-25,27-dihydroxy calix[4]arene with semicarbazide hydrochloride. This calix[4]arene-semicarbazone derivative was then covalently linked with commercially available Merrifield's peptide resin at the "lower-rim" to obtain polymeric chelating resin and its analytical properties were investigated. The resin was then used successfully for the separation and preconcentration of lanthanum(III), cerium(III), thorium(IV) and uranium(VI) prior to their determination by spectrophotometry and inductively coupled plasma atomic emission spectroscopy. The resin exhibits good separating ability with maximum sorption between pH 2.5-4.5 for Th(IV) and between pH 5.5-7.0 for U(VI) whereas La(III) and Ce(III) were found to have maximum sorption between pH 6.5-8.5. The elution studies were carried out with 0.01 M HCl for La(III) and Ce(III), 2.0 M HCl for Th(IV) and 0.25 M HCl for U(VI). The preconcentration factors for La(III), Ce(III), Th(IV) and U(VI) were 125, 130, 102 and 108, respectively. The resin shows good stability along with faster rate of equilibrium for all the metal ions. The influence of several ions (cations and anions) on the resin performance is also discussed. The relative standard deviation was between 96 and 98% with good analytical reliability. The proposed method was applied for the determination of metal ions in monazite sand and some standard geological materials. © 2002 Elsevier Science B.V. All rights reserved
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