Brain atlases have been used as spatial references to classify and tag either structural or functional topological information from brain images. Semantic information obtained from the existing image data is thus spatially mapped according the atlas descriptors. However the process of classifying and tagging brain images using an atlas is often tedious and mostly dependent on human observation and validation. At the same time, even when available, it is often difficult to use, particularly when using standard query and retrieve services in modern imaging repositories (e.g. DICOM based PACS).
In this work we propose NEArBy, a cloud based solution that provides query and retrieve services based on brain atlas semantics that can be easily integrated in existing DICOM based imaging repositories. Using a web interface, NEArBy supports not only typical DICOM query retrieve searches but also query tokens matching the brain atlas dictionary.
To automate the semantic tagging of the brain images we rely on external methods to identify relevant spatial features that are later labelled using standard brain atlas. Being DICOM a tag based standard, atlas related tags are then privately embedded into DICOM files as NEArBy JSON descriptors using lexicon as proposed in NeuroLex. These descriptors encode the mapping between feature type...
A search for a heavy Standard Model Higgs boson decaying via View the MathML sourceH→ZZ→ℓ+ℓ−qq¯, where ℓ=eℓ=e or μ , is presented. The search uses a data set of pp collisions at View the MathML sources=7 TeV, corresponding to an integrated luminosity of 4.7 fb−14.7 fb−1 collected in 2011 by the ATLAS detector at the CERN LHC. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section of a Higgs boson with a mass in the range between 200 and 600 GeV600 GeV are derived. A Standard Model Higgs boson with a mass in the range 300 GeV⩽mH⩽322 GeV300 GeV⩽mH⩽322 GeV or 353 GeV⩽mH⩽410 GeV353 GeV⩽mH⩽410 GeV is excluded at 95% CL. The corresponding expected exclusion range is 351 GeV⩽mH⩽404 GeV351 GeV⩽mH⩽404 GeV at 95% CL.; ATLAS Collaboration; ATLAS Collaboration Contributor: M. White for the University of Adelaide.
A search for the Standard Model Higgs boson in the H → WW(*) → ℓνℓν (ℓ = e,μ) decay mode is presented. The search is performed using proton–proton collision data corresponding to an integrated luminosity of 4.7 fb−1 at a centre-of-mass energy of 7 TeV collected during 2011 with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed. An upper bound is placed on the Higgs boson production cross section as a function of its mass. A Standard Model Higgs boson with mass in the range between 133 GeV and 261 GeV is excluded at 95% confidence level, while the expected exclusion range is from 127 GeV to 233 GeV.; ATLAS Collaboration; ATLAS Collaboration Contributor: M. White for the University of Adelaide.
A search for a Standard Model Higgs boson decaying via H →ZZ→ℓ + ℓ −ν¯ν , where ℓ represents electrons or muons, is presented. It is based on proton–proton collision data at √ s = 7 TeV, collected by the ATLAS experiment at the LHC during 2011 and corresponding to an integrated luminosity of 4.7 fb−1. The data agree with the expected Standard Model backgrounds. Upper limits on the Higgs boson production cross section are derived for Higgs boson masses between 200 GeV and 600 GeV and the production of a Standard Model Higgs boson with a mass in the range 319–558 GeV is excluded at the 95% confidence level.; ATLAS Collaboration; ATLAS Collaboration Contributor: M. White for the University of Adelaide.
This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at √ s = 7 TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the crosssection. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt = 16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb| = 1.03+0.16 −0.19 is derived assuming that the Wt production through |Vts| and |Vtd| is small.; ATLAS Collaboration; ATLAS Collaboration Contributor: M. White for the University of Adelaide.
A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3??????fb???1 of integrated luminosity at s???=8??????TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the standard model expectations. Limits are set on the mass scale in effective field theories that describe the interaction of dark matter and standard model particles, and on the cross section of Higgs production and decay to invisible particles. In addition, cross section limits on the anomalous production of W or Z bosons with large missing transverse momentum are set in two fiducial regions.
A search is presented for new particles in an extension to the Standard Model that includes a heavy Higgs boson (H0), an intermediate charged Higgs-boson pair (H??), and a light Higgs boson (h0). The analysis searches for events involving the production of a single heavy neutral Higgs boson which decays to the charged Higgs boson and a W boson, where the charged Higgs boson subsequently decays into a W boson and the lightest neutral Higgs boson decaying to a bottom???antibottom-quark pair. Such a cascade results in a W-boson pair and a bottom???antibottom-quark pair in the final state. Events with exactly one lepton, missing transverse momentum, and at least four jets are selected from a data sample corresponding to an integrated luminosity of 20.3??????fb???1, collected by the ATLAS detector in proton-proton collisions at s???=8??????TeV at the LHC. The data are found to be consistent with Standard Model predictions, and 95% confidence-level upper limits are set on the product of cross section and branching ratio. These limits range from 0.065 to 43 pb as a function of H0 and H?? masses, with mh0 fixed at 125 GeV.
A generic search for anomalous production of events with at least three charged leptons is presented. The search uses a pp-collision data sample at a center-of-mass energy of s???=7??????TeV corresponding to 4.6??????fb???1 of integrated luminosity collected in 2011 by the ATLAS detector at the CERN Large Hadron Collider. Events are required to contain at least two electrons or muons, while the third lepton may either be an additional electron or muon, or a hadronically decaying tau lepton. Events are categorized by the presence or absence of a reconstructed tau-lepton or Z-boson candidate decaying to leptons. No significant excess above backgrounds expected from Standard Model processes is observed. Results are presented as upper limits on event yields from non-Standard-Model processes producing at least three prompt, isolated leptons, given as functions of lower bounds on several kinematic variables. Fiducial efficiencies for model testing are also provided. The use of the results is illustrated by setting upper limits on the production of doubly charged Higgs bosons decaying to same-sign lepton pairs.
The production of K0S and ?? hadrons is studied in pp collision data at s???=0.9 and 7 TeV collected with the ATLAS detector at the LHC using a minimum-bias trigger. The observed distributions of transverse momentum, rapidity, and multiplicity are corrected to hadron level in a model-independent way within well-defined phase-space regions. The distribution of the production ratio of ?????? to ?? baryons is also measured. The results are compared with various Monte Carlo simulation models. Although most of these models agree with data to within 15% in the K0S distributions, substantial disagreements are found in the ?? distributions of transverse momentum.
This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4.7??????fb???1 of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at s???=7??????TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of ?????P, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving or a maximally CP violating production process. The measurements obtained, ?????PCPC=???0.035??0.014(stat)??0.037(syst) and ?????PCPV=0.020??0.016(stat)+0.013???0.017(syst), are in good agreement with the standard model prediction of negligible top quark polarization.
This Letter presents a search for pair production of heavy down-type quarks decaying via b??????Wt in the lepton+jets channel, as b???b????????W???tW+t?????bb??W+W???W+W??????l????bb??qq??qq??qq??. In addition to requiring exactly one lepton, large missing transverse momentum, and at least six jets, the invariant mass of nearby jet pairs is used to identify high transverse momentum W bosons. In data corresponding to an integrated luminosity of 1.04??????fb???1 from pp collisions at s???=7??????TeV recorded with the ATLAS detector, a heavy down-type quark with mass less than 480 GeV can be excluded at the 95% confidence level.
An inclusive search for anomalous production of two prompt, isolated muons with the same electric charge is presented. The search is performed in a data sample corresponding to 1.6??????fb???1 of integrated luminosity collected in 2011 at s???=7??????TeV with the ATLAS detector at the LHC. Muon pairs are selected by requiring two isolated muons of the same electric charge with pT>20??????GeV and |??|<2.5. Minimal requirements are placed on the rest of the event activity. The distribution of the invariant mass of the muon pair m(????) is found to agree well with the background expectation. Upper limits on the cross section for anomalous production of two muons with the same electric charge are placed as a function of m(????) within a fiducial region defined by the event selection. The fiducial cross-section limit constrains the like-sign top-quark pair-production cross section to be below 3.7 pb at 95% confidence level. The data are also analyzed to search for a narrow like-sign dimuon resonance as predicted for e.g. doubly charged Higgs bosons (H????). Assuming pair production of H???? bosons and a branching ratio to muons of 100% (33%), this analysis excludes masses below 355 (244) GeV and 251 (209) GeV for H???? bosons coupling to left-handed and right-handed fermions...
A search for the weak production of charginos and neutralinos decaying to a final state with three leptons (electrons or muons) and missing transverse momentum is presented. The analysis uses 2.06??????fb???1 of s???=7??????TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with standard model expectations in two signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric and simplified models. For the simplified models, degenerate lightest chargino and next-to-lightest neutralino masses up to 300 GeV are excluded for mass differences from the lightest neutralino up to 300 GeV.
A search for a heavy, CP-odd Higgs boson, A, decaying into a Z boson and a 125 GeV Higgs boson, h, with the ATLAS detector at the LHC is presented. The search uses proton???proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb???1. Decays of CP-even h bosons to ???? or bb pairs with the Z boson decaying to electron or muon pairs are considered, as well as h???bbh???bb decays with the Z boson decaying to neutrinos. No evidence for the production of an A boson in these channels is found and the 95% confidence level upper limits derived for ??(gg???A)??BR(A???Zh)??BR(h???ff??) are 0.098???0.013 pb for f=??f=?? and 0.57???0.014 pb for f=bf=b in a range of mA=220???1000 GeVmA=220???1000 GeV. The results are combined and interpreted in the context of two-Higgs-doublet models.
A search for a charged Higgs boson (H+) in ttbar decays is presented, where one of the top quarks decays via t->H+b, followed by H+->two jets (csbar). The other top quark decays to Wb, where the W boson then decays into a lepton (e/mu) and a neutrino. The data were recorded in pp collisions at sqrt(s) = 7TeV by the ATLAS detector at the LHC in 2011, and correspond to an integrated luminosity of 4.7 fb-1. With no observation of a signal, 95% confidence level (CL) upper limits are set on the decay branching ratio of top quarks to charged Higgs bosons varying between 5% and 1% for H+ masses between 90 GeV and 150 GeV, assuming Br(H+->csbar)=100%.; Fil: Aad, G.. Cern - European Organization For Nuclear Research; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - la Plata. Instituto de Fisica La Plata; Argentina;; Fil: González Silva, María Laura. Universidad Nacional de la Plata. Facultad de Cs.exactas. Instituto de Fisica de la Plata;; Fil: Otero y Garzon, Gustavo Javier.; Fil: Piegaia, Ricardo Nestor.; Fil: Romeo, Gaston Leonardo.; Fil: Alonso, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - la Plata. Instituto de Fisica La Plata; Argentina;; Fil: Anduaga...
Measurements are presented of differential crosss ections for top quark pair production in pp collisions at 7 TeV relative to the total inclusive top quark pair production cross-section. A data sample of 2.05 fb−1 recorded by the ATLAS detector at the Large Hadron Collider is used. Relative differential cross-sections are derived as a function of the invariant mass, the transverse momentum and the rapidity of the top quark pair system. Events are selected in the lepton (electron or muon) + jets channel. The backgroundsubtracted differential distributions are corrected for detector effects, normalized to the total inclusive top quark pair production cross-section and compared to theoretical predictions. The measurement uncertainties range typically between 10 % and 20 % and are generally dominated by systematic effects. No significant deviations from the Standard Model expectations are observed.; Fil: Aad, G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Instituto de Física La Plata; Argentina; Cern - European Organization For Nuclear Research;; Fil: Alonso, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - La Plata. Instituto de Física La Plata; Argentina;; Fil: Anduaga...
Measurements of the variation of inclusive jet suppression as a function of relative azimuthal angle, Delta phi, with respect to the elliptic event plane provide insight into the path-length dependence of jet quenching. ATLAS has measured the Delta phi dependence of jet yields in 0.14 nb^-1 of sqrt(s(NN))= 2.76 TeV Pb+Pb collisions at the LHC for jet transverse momenta p_T > 45 GeV in different collision centrality bins using an underlying event subtraction procedure that accounts for elliptic flow. The variation of the jet yield with Delta phi was characterized by the parameter, v_2^jet, and the ratio of out-of-plane (Delta phi ~ pi/2) to in-plane (Delta phi ~ 0) yields. Non-zero v_2^jet values were measured in all centrality bins for p_T < 160 GeV. The jet yields are observed to vary by as much as 20% between in-plane and out-of-plane directions.; Fil: Alconada Verzini, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - la Plata. Instituto de Fisica la Plata; Argentina; Cern - European Organization For Nuclear Research;; Fil: Monticelli, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - la Plata. Instituto de Fisica la Plata; Argentina;; Fil: Alonso...
This paper describes ameasurement of the flavour c√omposition of dijet events produced in pp collisions at s = 7 TeV using the ATLAS detector. The measurement uses the full 2010 data sample, corresponding to an integrated luminosity of 39 pb−1. Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. Kinematic variables, based on the properties of displaced decay vertices and optimised for jet flavour identification, are used in a multidimensional template fit to measure the fractions of these dijet flavour states as functions of the leading jet transverse momentum in the range 40 GeV to 500 GeV and jet rapidity |y| < 2.1. The fit results agree with the predictions of leading- and next-to-leading-order calculations, with the exception of the dijet fraction composed of bottom and light flavour jets, which is underestimated by all models at large transverse jet momenta. The ability to identify jets containing two b-hadrons, originating from e.g. gluon splitting, is demonstrated. The difference between bottom jet production rates in leading and subleading jets is consistent with the next-to-leading-order predictions.; Fil: Aad...
6 pages, 9 figures.-- Prepared for 14th IEEE-NPSS Real Time Conference 2005 (RT2005), 4-10 Jun 2005, Stockholm, Sweden.-- Published in: IEEE Transactions on Nuclear Science 53: 729-734 (2006), final full-text version of the paper available at: http://dx.doi.org/10.1109/TNS.2006.874727.; The ATLAS Semiconductor Tracker (SCT) together with the pixel and the transition radiation detectors will form the tracking system of the ATLAS experiment at LHC. It will consist of 20000 single-sided silicon microstrip sensors assembled back-to-back into modules mounted on four concentric barrels and two end-cap detectors formed by nine disks each. The SCT module production and testing has finished while the macro-assembly is well under way. After an overview of the layout and the operating environment of the SCT, a description of the readout electronics design and operation requirements will be given. The quality control procedure and the DAQ software for assuring the electrical functionality of hybrids and modules will be discussed. The focus will be on the electrical performance results obtained during the assembly and testing of the end-cap SCT modules.; This work was supported in part by the EU under the RTN contract: HPRN-CT-2002-00292
Probe for New Physics.; Peer reviewed
A search for a heavy, CP-odd Higgs boson, A, decaying into a Z boson and a 125 GeV Higgs boson, h, with the ATLAS detector at the LHC is presented. The search uses proton–proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb¯¹. Decays of CP-even h bosons to ττ or bb pairs with the Z boson decaying to electron or muon pairs are considered, as well as h→bb decays with the Z boson decaying to neutrinos. No evidence for the production of an A boson in these channels is found and the 95% confidence level upper limits derived for σ(gg → A) x BR (A → Zh) x BR (h → fḟ) are 0.098–0.013 pb for f=τ and 0.57–0.014 pb for f=b in a range of mA=220–1000 GeV. The results are combined and interpreted in the context of two-Higgs-doublet models.