12 research outputs found

    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

    Get PDF

    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

    Get PDF

    Investigating the barriers to increase Levels of Automation. : A case study in pre-assembly of tap changer assembly line.

    No full text
    The overarching goal of this thesis is to investigate and explore the barriers that a company would face while increasing the Levels of Automation (LoA), in the preassembly production unit. To achieve the primary goal of investigating the barriers this study takes a threefold approach. Firstly, the current LoA was measured for the preassembly workstations. This measurement was conducted by incorporating an existing methodology adapted from the literature review known as DYNAMO++ methodology. This method is incorporated such that, the current LoA of the preassembly workstations could be measured and analysed. The current LoA of the preassembly workstations are analysed to investigate the potential workstations where LoA could be increased, in line with the company’s triggers for implementing automation. For this, experiences of the personnel’s belonging to the operational level of preassembly workstations were incorporated, to find the scope of improvements for increasing the LoA. Additionally, the company’s triggers for implementing automation was investigated from the managerial level. The research questions were answered by adapting an explorative, single case study method. Additionally, four types of data collection techniques were used, such as – interviews, focus groups, observations, and document analysis. Subsequently, source triangulation was adapted to analyse the data collected; to develop a comprehensive understanding of the barriers identified., Finally, the barriers faced by the company to increase LoA are identified by considering the implications that the improvement opportunities would impose upon the production systems environment. The identified barriers were then categorised further based on factors that exist internal as well as external to the production systems environment. The barriers identified in this study highlights various factors that the management must consider beforehand while initiating automation decisions in future automation projects in the preassembly area. Regardless of the barriers faced by the company, there are more opportunities to improve manufacturing processes through automation technologies. This thesis contributes to the knowledge of the factors that restrain the implementation of automation technologies and how companies could deal with it

    Search for Scalar Diphoton Resonances in the Mass Range 6560065-600 GeV with the ATLAS Detector in pppp Collision Data at s\sqrt{s} = 8 TeVTeV

    No full text
    A search for scalar particles decaying via narrow resonances into two photons in the mass range 65–600 GeV is performed using 20.3fb120.3\text{}\text{}{\mathrm{fb}}^{-1} of s=8TeV\sqrt{s}=8\text{}\text{}\mathrm{TeV} pppp collision data collected with the ATLAS detector at the Large Hadron Collider. The recently discovered Higgs boson is treated as a background. No significant evidence for an additional signal is observed. The results are presented as limits at the 95% confidence level on the production cross section of a scalar boson times branching ratio into two photons, in a fiducial volume where the reconstruction efficiency is approximately independent of the event topology. The upper limits set extend over a considerably wider mass range than previous searches

    Search for Higgs and ZZ Boson Decays to J/ψγJ/\psi\gamma and Υ(nS)γ\Upsilon(nS)\gamma with the ATLAS Detector

    No full text
    A search for the decays of the Higgs and ZZ bosons to J/ψγJ/\psi\gamma and Υ(nS)γ\Upsilon(nS)\gamma (n=1,2,3n=1,2,3) is performed with pppp collision data samples corresponding to integrated luminosities of up to 20.3fb120.3\mathrm{fb}^{-1} collected at s=8TeV\sqrt{s}=8\mathrm{TeV} with the ATLAS detector at the CERN Large Hadron Collider. No significant excess of events is observed above expected backgrounds and 95% CL upper limits are placed on the branching fractions. In the J/ψγJ/\psi\gamma final state the limits are 1.5×1031.5\times10^{-3} and 2.6×1062.6\times10^{-6} for the Higgs and ZZ bosons, respectively, while in the Υ(1S,2S,3S)γ\Upsilon(1S,2S,3S)\,\gamma final states the limits are (1.3,1.9,1.3)×103(1.3,1.9,1.3)\times10^{-3} and (3.4,6.5,5.4)×106(3.4,6.5,5.4)\times10^{-6}, respectively

    Search for Scalar-Charm pair production in pp collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

    No full text
    The results of a dedicated search for pair production of scalar partners of charm quarks are reported. The search is based on an integrated luminosity of 20.3 fb1^{-1} of pp collisions at s=8\sqrt{s}=8 TeV recorded with the ATLAS detector at the LHC. The search is performed using events with large missing transverse momentum and at least two jets, where the two leading jets are each tagged as originating from c-quarks. Events containing isolated electrons or muons are vetoed. In an R-parity-conserving minimal supersymmetric scenario in which a single scalar-charm state is kinematically accessible, and where it decays exclusively into a charm quark and a neutralino, 95% confidence-level upper limits are obtained in the scalar-charm-neutralino mass plane such that, for neutralino masses below 200 GeV, scalar-charm masses up to 490 GeV are excluded

    Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the H??????? and H???ZZ*???4??? Decay Channels at s\sqrt{s}=8??????TeV with the ATLAS Detector

    No full text
    Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3~fb1^{-1} of pppp collisions produced by the Large Hadron Collider at a center-of-mass energy of s=8\sqrt{s} = 8 TeV and recorded by the ATLAS detector. Cross sections are obtained from measured HγγH \rightarrow \gamma \gamma and HZZ4H \rightarrow ZZ ^{*}\rightarrow 4\ell event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be σppH=33.0±5.3(stat)±1.6(sys)pb\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3  fb-1 of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of s=8  TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H→γγ and H→ZZ*→4ℓ event yields, which are combined accounting for detector efficiencies, fiducial acceptances, and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be σpp→H=33.0±5.3 (stat)±1.6 (syst)  pb. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb1^{-1} of pppp collisions produced by the Large Hadron Collider at a center-of-mass energy of s=8\sqrt{s} = 8 TeV and recorded by the ATLAS detector. Cross sections are obtained from measured HγγH \rightarrow \gamma \gamma and HZZ4H \rightarrow ZZ ^{*}\rightarrow 4\ell event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be σppH=33.0±5.3(stat)±1.6(sys)pb\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}. The measurements are compared to state-of-the-art predictions

    Measurement of differential J/ψJ/\psi production cross-sections and forward-backward ratio in p+Pb collisions with the ATLAS detector

    No full text
    Measurements of differential cross-sections for J/ψJ/\psi production in p+Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV at the LHC with the ATLAS detector are presented. The data set used corresponds to an integrated luminosity of 28.1 nb1^{-1}. The J/ψJ/\psi mesons are reconstructed in the dimuon decay channel over the transverse momentum range 8<pT<308<p_{\mathrm{T}}<30 GeV and over the center-of-mass rapidity range 2.87<y<1.94-2.87<y^{*}<1.94. Prompt J/ψJ/\psi are separated from J/ψJ/\psi resulting from bb-hadron decays through an analysis of the distance between the J/ψJ/\psi decay vertex and the event primary vertex. The differential cross-section for production of nonprompt J/ψJ/\psi is compared to a FONLL calculation that does not include nuclear effects. Forward-backward production ratios are presented and compared to theoretical predictions. These results constrain the kinematic dependence of nuclear modifications of charmonium and bb-quark production in p+Pb collisions
    corecore