739 research outputs found

    New life cycles for drosscapes: Recycle of a brownfield along the waterfront of Barcelona

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    Ponència presentada a: Session 7: Participación en planeamiento / Participation in planning. Environmental and hermeneutic plannin

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

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    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

    Performance Assessment in Fingerprinting and Multi Component Quantitative NMR Analyses

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    An interlaboratory comparison (ILC) was organized with the aim to set up quality control indicators suitable for multicomponent quantitative analysis by nuclear magnetic resonance (NMR) spectroscopy. A total of 36 NMR data sets (corresponding to 1260 NMR spectra) were produced by 30 participants using 34 NMR spectrometers. The calibration line method was chosen for the quantification of a five-component model mixture. Results show that quantitative NMR is a robust quantification tool and that 26 out of 36 data sets resulted in statistically equivalent calibration lines for all considered NMR signals. The performance of each laboratory was assessed by means of a new performance index (named Qp-score) which is related to the difference between the experimental and the consensus values of the slope of the calibration lines. Laboratories endowed with a Qp-score falling within the suitable acceptability range are qualified to produce NMR spectra that can be considered statistically equivalent in terms of relative intensities of the signals. In addition, the specific response of nuclei to the experimental excitation/relaxation conditions was addressed by means of the parameter named NR. NR is related to the difference between the theoretical and the consensus slopes of the calibration lines and is specific for each signal produced by a well-defined set of acquisition parameters

    New high statistics measurement of Ke4K_{e4} decay form factors and ππ\pi\pi scattering phase shifts

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    We report results from a new measurement of the Ke4K_{e4} decay K±π+πe±νK^{\pm} \rightarrow \pi^{+}\pi^{-}e^{\pm}\nu by the NA48/2 collaboration at the CERN SPS, based on a partial sample of more than 670000 Ke4K_{e4} decays in both charged modes collected in 2003. The form factors of the hadronic current (F, G, H) and ππ\pi\pi phase difference (δ=δsδp\delta=\delta_{s}-\delta_{p}) have been measured in ten independent bins of the ππ\pi\pi mass spectrum to investigate the variation. A sizeable acceptance at large ππ\pi\pi mass, a low background and a very good resolution contribute to an improved experimental accuracy, a factor two better than in the previous measurement, when extracting the ππ\pi\pi scattering lengths a00a^{0}_{0} and a02a^{2}_{0}. Under the assumption of isospin symmetry and using numerical solutions of the Roy equations, the following values are obtained in the plane (a00,a02):a00=0.233±0.016stat±0.007syst,a02=0.0471±0.011stat±0.004systa^{0}_{0}, a^{2}_{0}): a^{0}_{0}=0.233 \pm 0.016_{stat} \pm 0.007_{syst}, a^{2}_{0}=-0.0471 \pm 0.011_{stat} \pm 0.004_{syst}. The presence of potentially large isospin effects is also considered and will allow comparison with precise predictions from Chiral Perturbation Theory

    Search for direct CP violating charge asymmetries in K±π±π+πK^\pm\to\pi^\pm\pi^+\pi^- and K±π±π0π0K^\pm\to\pi^\pm\pi^0\pi^0 decays

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    A measurement of the direct CP violating charge asymmetries of the Dalitz plot linear slopes Ag=(g+g)/(g++g)A_g=(g^+-g^-)/(g^++g^-) in K±π±π+πK^\pm\to\pi^\pm\pi^+\pi^- and K±π±π0π0K^\pm\to\pi^\pm\pi^0\pi^0 decays by the NA48/2 experiment at CERN SPS is presented. A new technique of asymmetry measurement involving simultaneous K+K^+ and KK^- beams and a large data sample collected allowed a result of an unprecedented precision. The charge asymmetries were measured to be Agc=(1.5±2.2)×104A^c_g=(-1.5\pm2.2)\times10^{-4} with 3.11×1093.11\times 10^9 K±π±π+πK^{\pm}\to\pi^\pm\pi^+\pi^- decays, and Agn=(1.8±1.8)×104A^n_g=(1.8\pm1.8)\times10^{-4} with 9.13×1079.13\times 10^7 K±π±π0π0K^{\pm}\to\pi^\pm\pi^0\pi^0 decays. The precision of the results is limited mainly by the size of the data sample.Comment: 29 pages, 9 figures. An updated version accepted by the EPJ
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