13 research outputs found

    Toward optimal X-ray flux utilization in breast CT

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    A realistic computer-simulation of a breast computed tomography (CT) system and subject is constructed. The model is used to investigate the optimal number of views for the scan given a fixed total X-ray fluence. The reconstruction algorithm is based on accurate solution to a constrained, TV-minimization problem, which has received much interest recently for sparse-view CT data.Comment: accepted to the 11th International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine 201

    Search for dark matter in events with heavy quarks and missing transverse momentum in pp collisions with the ATLAS detector

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    This article reports on a search for dark matter pair production in association with bottom or top quarks in 20.3 fb(-1) of pp collisions collected at root s = 8 TeV by the ATLAS detector at the LHC. Events with large missing transverse momentum are selected when produced in association with high-momentum jets of which one or more are identified as jets containing b-quarks. Final states with top quarks are selected by requiring a high jet multiplicity and in some cases a single lepton. The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles. Limits on the dark-matter-nucleon cross-section for spin-independent and spin-dependent interactions are also provided. These limits are particularly strong for low-mass dark matter. Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter

    Search for dark matter in events with heavy quarks and missing transverse momentum in pp collisions with the ATLAS detector

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    This article reports on a search for dark matter pair production in association with bottom or top quarks in 20.3 fb(-1) of pp collisions collected at root s = 8 TeV by the ATLAS detector at the LHC. Events with large missing transverse momentum are selected when produced in association with high-momentum jets of which one or more are identified as jets containing b-quarks. Final states with top quarks are selected by requiring a high jet multiplicity and in some cases a single lepton. The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles. Limits on the dark-matter-nucleon cross-section for spin-independent and spin-dependent interactions are also provided. These limits are particularly strong for low-mass dark matter. Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter

    Observation of the rare Bs0oμ+μB^0_so\mu^+\mu^- decay from the combined analysis of CMS and LHCb data

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    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

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    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

    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

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    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

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    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

    Finska tingsdomares bedömningar av partsutlåtanden givna på plats i rätten eller via videokonferens

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    Professionals within the judicial system sometimes believe they can assess whether someone is lying or not based on cues such as body language and emotional expression. Research has, however, shown that this is impossible. The Finnish Supreme Court has also given rulings in accordance with this demonstrated fact. There has also been previous research on whether party or witness statements are assessed differently in court depending on whether they are given live, via videoconference, or via prerecorded video. In the present study, we investigated how a Finnish sample of district judges (N=47) assigned probative value to different variables concerning the statement or the statement giver, such as body language and emotional expression. We also investigated the connection between the judges’ beliefs about the relevance of body language and emotional expression and their preference for live statements or statements via videoconference. The judges reported assigning equal amounts of probative value to statements given live and statements given via videoconference. However, judges found it easier to detect deception live, and this preference correlated with how relevant they thought body language is when assessing the probative value of the statement. In other words, a slight bias to assess live statements more favorably than statements given via videoconference might still exist. More effort needs to be put into making judges and Supreme Courts aware of robust scientific results that have been the subject of decades of research, such as the fact that one cannot assess whether someone is lying or not based on cues such as body language

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

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    A search for the decays of the Higgs and Z bosons to J/ψγ and ϒ(nS)γ (n=1,2,3) is performed with pp collision data samples corresponding to integrated luminosities of up to 20.3 fb-1 collected at s=8 TeV with the ATLAS detector at the CERN Large Hadron Collider. No significant excess of events is observed above expected backgrounds and 95% C.L. upper limits are placed on the branching fractions. In the J/ψγ final state the limits are 1.5×10-3 and 2.6×10-6 for the Higgs and Z boson decays, respectively, while in the ϒ(1S,2S,3S)γ final states the limits are (1.3,1.9,1.3)×10-3 and (3.4,6.5,5.4)×10-6, respectively
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