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Showing papers by "Technical University of Dortmund published in 2014"


Journal ArticleDOI
M. G. Aartsen1, Markus Ackermann, Jenni Adams2, Juanan Aguilar3  +299 moreInstitutions (41)
TL;DR: Results from an analysis with a third year of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8) GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ.
Abstract: A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8) GeV cm(-2) s(-1) sr(-1) per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7 sigma. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

1,183 citations


Journal ArticleDOI
Roel Aaij, Bernardo Adeva1, Marco Adinolfi2, A. Affolder3  +698 moreInstitutions (50)
TL;DR: The value of the ratio of branching fractions for the dilepton invariant mass squared range 1 < q(2) < 6 GeV(2)/c(4) is measured to be 0.745(-0.074)(+0.090)(stat) ± 0.036(syst).
Abstract: A measurement of the ratio of the branching fractions of the B+→K+μ+μ− and B+→K+e+e− decays is presented using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1, recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. The value of the ratio of branching fractions for the dilepton invariant mass squared range 1

1,017 citations


Journal ArticleDOI
TL;DR: OpenML as discussed by the authors is a place for machine learning researchers to share and organize data in fine detail, so that they can work more effectively, be more visible, and collaborate with others to tackle harder problems.
Abstract: Many sciences have made significant breakthroughs by adopting online tools that help organize, structure and mine information that is too detailed to be printed in journals. In this paper, we introduce OpenML, a place for machine learning researchers to share and organize data in fine detail, so that they can work more effectively, be more visible, and collaborate with others to tackle harder problems. We discuss how OpenML relates to other examples of networked science and what benefits it brings for machine learning research, individual scientists, as well as students and practitioners.

855 citations


Journal ArticleDOI
TL;DR: The aim of the paper is to focus on the industrial aspects of scheduling and discuss the main characteristics, including strengths and weaknesses of the presented approaches, as well as some lessons learned from industry.

439 citations


Journal ArticleDOI
J. P. Lees1, V. Poireau1, V. Tisserand1, E. Grauges2  +308 moreInstitutions (73)
TL;DR: In this article, the authors presented a search for a dark photon in the reaction e^{+}e^{-}→γA^{'], A^{'}→e''+''e''-e''−γA''−E''−μ'' −μ'' -E'' −γA''.
Abstract: Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the so-called dark photon (A^{'}), connecting the dark sector to the standard model. We present a search for a dark photon in the reaction e^{+}e^{-}→γA^{'}, A^{'}→e^{+}e^{-}, μ^{+}μ^{-} using 514 fb^{-1} of data collected with the BABAR detector. We observe no statistically significant deviations from the standard model predictions, and we set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of 10^{-4}-10^{-3} for dark photon masses in the range 0.02-10.2 GeV. We further constrain the range of the parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon.

436 citations


Journal ArticleDOI
Roel Aaij, Bernardo Adeva1, Marco Adinolfi2, A. A. Affolder3  +710 moreInstitutions (63)
TL;DR: In this article, the authors measured the isospin asymmetries of the B (0) -> K ( 0) mu (+) mu (-), B (1) → K (1)-m (+) m mu (-) and B (2)→ K (2)-m (-) m (-), respectively.
Abstract: The isospin asymmetries of B -> K mu (+) mu (-) and B -> K (*) mu (+) mu (-) decays and the partial branching fractions of the B (0) -> K (0) mu (+) mu (-), B (+) -> K (+) mu (+) mu (-) and B (+) -> K (*+) mu (+) mu (-) decays are measured as functions of the dimuon mass squared, q (2). The data used correspond to an integrated luminosity of 3 fb(-1) from proton-proton collisions collected with the LHCb detector at centre-of-mass energies of 7 TeV and 8 TeV in 2011 and 2012, respectively. The isospin asymmetries are both consistent with the Standard Model expectations. The three measured branching fractions favour lower values than their respective theoretical predictions, however they are all individually consistent with the Standard Model.

386 citations


Journal ArticleDOI
Roel Aaij, Bernardo Adeva1, Marco Adinolfi2, A. A. Affolder3  +695 moreInstitutions (49)
TL;DR: The observed evolution of the Z(4430)^{-} amplitude with the ψ^{ fb^{-1} mass establishes the resonant nature of this particle.
Abstract: Resonant structures in B-0 -> psi'pi K--(+) decays are analyzed by performing a four-dimensional fit of the decay amplitude, using pp collision data corresponding to 3 fb(-1) collected with the LHCb detector. The data cannot be described with K+pi(-) resonances alone, which is confirmed with a model-independent approach. A highly significant Z(4430)(-) -> psi'pi(-) component is required, thus confirming the existence of this state. The observed evolution of the Z(4430)(-) amplitude with the psi'pi(-) mass establishes the resonant nature of this particle. The mass and width measurements are substantially improved. The spin parity is determined unambiguously to be 1(+).

386 citations


Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2871 moreInstitutions (167)
TL;DR: In this article, the authors presented the electron and photon energy calibration achieved with the ATLAS detector using about 25 fb(-1) of LHC proton-proton collision data taken at center-of-mass energies of root s = 7 and 8 TeV.
Abstract: This paper presents the electron and photon energy calibration achieved with the ATLAS detector using about 25 fb(-1) of LHC proton-proton collision data taken at centre-of-mass energies of root s = 7 and 8 TeV. The reconstruction of electron and photon energies is optimised using multivariate algorithms. The response of the calorimeter layers is equalised in data and simulation, and the longitudinal profile of the electromagnetic showers is exploited to estimate the passive material in front of the calorimeter and reoptimise the detector simulation. After all corrections, the Z resonance is used to set the absolute energy scale. For electrons from Z decays, the achieved calibration is typically accurate to 0.05% in most of the detector acceptance, rising to 0.2% in regions with large amounts of passive material. The remaining inaccuracy is less than 0.2-1% for electrons with a transverse energy of 10 GeV, and is on average 0.3% for photons. The detector resolution is determined with a relative inaccuracy of less than 10% for electrons and photons up to 60 GeV transverse energy, rising to 40% for transverse energies above 500 GeV.

361 citations


Journal ArticleDOI
TL;DR: This work reports a symmetric ‘micro-scallop’, a single-hinge microswimmer that can propel in shear thickening and shear thinning fluids by reciprocal motion at low Re, and indicates that the net propulsion is caused by modulation of the fluid viscosity upon varying the shear rate.
Abstract: Biological microorganisms swim with flagella and cilia that execute nonreciprocal motions for low Reynolds number (Re) propulsion in viscous fluids. This symmetry requirement is a consequence of Purcell's scallop theorem, which complicates the actuation scheme needed by microswimmers. However, most biomedically important fluids are non-Newtonian where the scallop theorem no longer holds. It should therefore be possible to realize a microswimmer that moves with reciprocal periodic body-shape changes in non-Newtonian fluids. Here we report a symmetric 'micro-scallop', a single-hinge microswimmer that can propel in shear thickening and shear thinning (non-Newtonian) fluids by reciprocal motion at low Re. Excellent agreement between our measurements and both numerical and analytical theoretical predictions indicates that the net propulsion is caused by modulation of the fluid viscosity upon varying the shear rate. This reciprocal swimming mechanism opens new possibilities in designing biomedical microdevices that can propel by a simple actuation scheme in non-Newtonian biological fluids.

360 citations


Journal ArticleDOI
TL;DR: In this article, an analysis and simulation of crack propagation behavior considering laser additive manufacturing specific defects, such as porosity and surface roughness, is presented for the mechanical characterization of laser additive manufactured titanium alloy Ti-6Al-4V.

357 citations


Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2911 moreInstitutions (209)
TL;DR: In this paper, a measurement of the Z/gamma* boson transverse momentum spectrum using ATLAS proton-proton collision data at a centre-of-mass energy of root s = 7TeV at the LHC is described.
Abstract: This paper describes a measurement of the Z/gamma* boson transverse momentum spectrum using ATLAS proton-proton collision data at a centre-of-mass energy of root s = 7TeV at the LHC. The measurement is performed in the Z/gamma* -> e(+)e(-) and Z/gamma* -> mu(+)mu(-) channels, using data corresponding to an integrated luminosity of 4.7 fb(-1). Normalized differential cross sections as a function of the Z/gamma* boson transverse momentum are measured for transverse momenta up to 800 GeV. The measurement is performed inclusively for Z/gamma* rapidities up to 2.4, as well as in three rapidity bins. The channel results are combined, compared to perturbative and resummed QCD calculations and used to constrain the parton shower parameters of Monte Carlo generators.

Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2916 moreInstitutions (211)
TL;DR: In this article, a search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented.
Abstract: A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector.

Journal ArticleDOI
TL;DR: Hybrid manufacturing processes are based on the simultaneous and controlled interaction of process mechanisms and/or energy sources/tools having a significant effect on the process performance as discussed by the authors, which can have a large influence on the processing/manufacturing characteristics resulting in higher machinability, reductions of process forces and tool wear.

Journal ArticleDOI
TL;DR: A platform that extends the hanging-drop technology, used for multi-cellular spheroid formation, to multifunctional complex microfluidic networks, and is a promising technology for 'body-on-a-chip'-related research.
Abstract: Integration of multiple three-dimensional microtissues into microfluidic networks enables new insights in how different organs or tissues of an organism interact. Here, we present a platform that extends the hanging-drop technology, used for multi-cellular spheroid formation, to multifunctional complex microfluidic networks. Engineered as completely open, 'hanging' microfluidic system at the bottom of a substrate, the platform features high flexibility in microtissue arrangements and interconnections, while fabrication is simple and operation robust. Multiple spheroids of different cell types are formed in parallel on the same platform; the different tissues are then connected in physiological order for multi-tissue experiments through reconfiguration of the fluidic network. Liquid flow is precisely controlled through the hanging drops, which enable nutrient supply, substance dosage and inter-organ metabolic communication. The possibility to perform parallelized microtissue formation on the same chip that is subsequently used for complex multi-tissue experiments renders the developed platform a promising technology for 'body-on-a-chip'-related research.

Journal ArticleDOI
TL;DR: This paper introduces OpenML, a place for machine learning researchers to share and organize data in fine detail, so that they can work more effectively, be more visible, and collaborate with others to tackle harder problems.
Abstract: Many sciences have made significant breakthroughs by adopting online tools that help organize, structure and mine information that is too detailed to be printed in journals. In this paper, we introduce OpenML, a place for machine learning researchers to share and organize data in fine detail, so that they can work more effectively, be more visible, and collaborate with others to tackle harder problems. We discuss how OpenML relates to other examples of networked science and what benefits it brings for machine learning research, individual scientists, as well as students and practitioners.

Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2870 moreInstitutions (169)
TL;DR: The performance of the ATLAS muon reconstruction during the LHC run withpp collisions at s=7–8 TeV in 2011–2012 is presented, focusing mainly on data collected in 2012.
Abstract: This paper presents the performance of the ATLAS muon reconstruction during the LHC run with pp collisions at root s = 7-8 TeV in 2011-2012, focusing mainly on data collected in 2012. Measurements ...

Journal ArticleDOI
Georges Aad1, T. Abajyan2, Brad Abbott3, Jalal Abdallah4  +2885 moreInstitutions (169)
TL;DR: In this article, the electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at TeV and corresponding to an integrated luminosity of 4.7 fb.
Abstract: Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at TeV and corresponding to an integrated luminosity of 4.7 fb. Tag-and-probe methods using events with leptonic decays of and bosons and mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.

Journal ArticleDOI
TL;DR: In this paper, the authors identify dimension-six operators that could explain this deviation and study constraints from other measurements, and present two leptoquark models which can explain the FCNC data and give predictions for the LHC and rare decays.
Abstract: Flavor changing neutral current (FCNC) | Δ B | = | Δ S | = 1 processes are sensitive to possible new physics at the electroweak scale and beyond, providing detailed information about flavor, chirality and Lorentz structure. Recently the LHCb Collaboration announced a 2.6 σ deviation in the measurement of R K = B ( B ¯ → K ¯ μ μ ) / B ( B ¯ → K ¯ e e ) from the standard model’s prediction of lepton universality. We identify dimension-six operators that could explain this deviation and study constraints from other measurements. Vector and axial-vector four-fermion operators with flavor structure s ¯ b l ¯ l can provide a good description of the data. Tensor operators cannot describe the data. Pseudoscalar and scalar operators only fit the data with some fine-tuning; they can be further probed with the B ¯ → K ¯ e e angular distribution. The data appear to point towards C 9 NP μ = - C 10 NP μ 0 , an SU ( 2 ) L invariant direction in parameter space supported by R K , the B ¯ → K ¯ * μ μ forward-backward asymmetry and the B ¯ s → μ μ branching ratio, which is currently allowed to be smaller than the standard model prediction. We present two leptoquark models which can explain the FCNC data and give predictions for the LHC and rare decays.

Journal ArticleDOI
TL;DR: A review of cutting edge preparation technologies and methods for cutting edge characterization can be found in this article, where the authors discuss the influence of cutting-edge geometry on chip formation, material flow, as well as mechanical and thermal loads on the tool.

Journal ArticleDOI
TL;DR: In this paper, the authors present an overview of recent developments in simulating machining and grinding processes along the NC tool path in virtual environments, and present the present and future challenges to achieving a more accurate and efficient virtual machining process simulation and optimization system.

Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2916 moreInstitutions (196)
TL;DR: In this paper, a measurement of the production processes of the recently discovered Higgs boson is performed in the two-photon final state using 4.5 fb(-1) of proton-proton collisions data at root s = 7 TeV and 20.4 GeV.
Abstract: A measurement of the production processes of the recently discovered Higgs boson is performed in the two-photon final state using 4.5 fb(-1) of proton-proton collisions data at root s = 7 TeV and 20.3 fb(-1) at root s = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. The number of observed Higgs boson decays to diphotons divided by the corresponding Standard Model prediction, called the signal strength, is found to be mu = 1.17 +/- 0.27 at the value of the Higgs boson mass measured by ATLAS, m(H) = 125.4 GeV. The analysis is optimized to measure the signal strengths for individual Higgs boson production processes at this value of m(H). They are found to be mu(ggF) = 1.32 +/- 0.38, mu(VBF) = 0.8 +/- 0.7, mu(WH) = 1.0 +/- 1.6, mu(ZH) = 0.1(-0.1)(+3.7), and mu t (t) over barH = 1.6(-1.8)(+2.7), for Higgs boson production through gluon fusion, vector-boson fusion, and in association with a W or Z boson or a top-quark pair, respectively. Compared with the previously published ATLAS analysis, the results reported here also benefit from a new energy calibration procedure for photons and the subsequent reduction of the systematic uncertainty on the diphoton mass resolution. No significant deviations from the predictions of the Standard Model are found.

Journal ArticleDOI
TL;DR: This study reveals that the content-based tag cloud explanations are particularly helpful to increase the user-perceived level of transparency and to increase user satisfaction even though they demand higher cognitive effort from the user.
Abstract: Recommender systems help users locate possible items of interest more quickly by filtering and ranking them in a personalized way. Some of these systems provide the end user not only with such a personalized item list but also with an explanation which describes why a specific item is recommended and why the system supposes that the user will like it. Besides helping the user understand the output and rationale of the system, the provision of such explanations can also improve the general acceptance, perceived quality, or effectiveness of the system. In recent years, the question of how to automatically generate and present system-side explanations has attracted increased interest in research. Today some basic explanation facilities are already incorporated in e-commerce Web sites such as Amazon.com. In this work, we continue this line of recent research and address the question of how explanations can be communicated to the user in a more effective way. In particular, we present the results of a user study in which users of a recommender system were provided with different types of explanation. We experimented with 10 different explanation types and measured their effects in different dimensions. The explanation types used in the study include both known visualizations from the literature as well as two novel interfaces based on tag clouds. Our study reveals that the content-based tag cloud explanations are particularly helpful to increase the user-perceived level of transparency and to increase user satisfaction even though they demand higher cognitive effort from the user. Based on these insights and observations, we derive a set of possible guidelines for designing or selecting suitable explanations for recommender systems.

Journal ArticleDOI
TL;DR: Preparing a shape‐adaptive, contact‐killing coating by tethering quaternary‐ammonium‐compounds onto hyperbranched polyurea coatings, able to kill adhering bacteria by partially enveloping them, which causes removal of membrane lipids and eventually lead to bacterial death.
Abstract: Quaternary-ammonium-compounds are potent cationic antimicrobials used in everyday consumer products. Surface-immobilized, quaternary-ammonium-compounds create an antimicrobial contact-killing coating. We describe the preparation of a shape-adaptive, contact-killing coating by tethering quaternary-ammonium-compounds onto hyperbranched polyurea coatings, able to kill adhering bacteria by partially enveloping them. Even after extensive washing, coatings caused high contact-killing of Staphylococcus epidermidis, both in culture-based assays and through confocal-laser-scanning-microscopic examination of the membrane-damage of adhering bacteria. In culture-based assays, at a challenge of 1600 CFU/cm(2), contact-killing was >99.99%. The working-mechanism of dissolved quaternary-ammonium-compounds is based on their interdigitation in bacterial membranes, but it is difficult to envisage how immobilized quaternary-ammonium-molecules can exert such a mechanism of action. Staphylococcal adhesion forces to hyperbranched quaternary-ammonium coatings were extremely high, indicating that quaternary-ammonium-molecules on hyperbranched polyurea partially envelope adhering bacteria upon contact. These lethally strong adhesion forces upon adhering bacteria then cause removal of membrane lipids and eventually lead to bacterial death.

Journal ArticleDOI
16 Oct 2014-Nature
TL;DR: The existence of Rydberg excitons in the copper oxide Cu2O, with principal quantum numbers as large as n = 25, is demonstrated, which may allow the formation of ordered exciton phases or the sensing of elementary excitations in their surroundings on a quantum level.
Abstract: Rydberg excitons (condensed-matter analogues of hydrogen atoms) are shown to exist in single-crystal copper oxide with principal quantum numbers as large as n = 25 and giant wavefunctions with extensions of around two micrometres; this has implications for research in condensed-matter optics. Excitons, electron–hole pairs that play an essential role in the optical properties of semiconductors, can be viewed as condensed-matter analogues of hydrogen atoms, with a similar excitation spectrum. Dietmar Frohlich and colleagues extend the series of excitations from the previous record of principal quantum number n = 12, to n = 25 for excitons in single crystal cuprous oxide. At such high quantum numbers, the wave function of the excitons becomes giant, around 2 micrometres, and it is expected that these giant excitons (also called Rydberg excitons) strongly interact with each other. The authors observe evidence for a blockade effect where the presence of an exciton prevents excitation of another exciton in its vicinity. This work opens new research directions for optics in condensed matter. A highly excited atom having an electron that has moved into a level with large principal quantum number is a hydrogen-like object, termed a Rydberg atom. The giant size of Rydberg atoms1 leads to huge interaction effects. Monitoring these interactions has provided insights into atomic and molecular physics on the single-quantum level. Excitons—the fundamental optical excitations in semiconductors2, consisting of an electron and a positively charged hole—are the condensed-matter analogues of hydrogen. Highly excited excitons with extensions similar to those of Rydberg atoms are of interest because they can be placed and moved in a crystal with high precision using microscopic energy potential landscapes. The interaction of such Rydberg excitons may allow the formation of ordered exciton phases or the sensing of elementary excitations in their surroundings on a quantum level. Here we demonstrate the existence of Rydberg excitons in the copper oxide Cu2O, with principal quantum numbers as large as n = 25. These states have giant wavefunction extensions (that is, the average distance between the electron and the hole) of more than two micrometres, compared to about a nanometre for the ground state. The strong dipole–dipole interaction between such excitons is indicated by a blockade effect in which the presence of one exciton prevents the excitation of another in its vicinity.

Journal ArticleDOI
M. G. Aartsen1, Rasha Abbasi2, Markus Ackermann, Jenni Adams3  +288 moreInstitutions (39)
TL;DR: In this article, the authors describe methods and performance of reconstructing charged particle energies and topologies from the observed Cherenkov light yield, including techniques to measure the energies of uncontained muon tracks, achieving average uncertainties in electromagnetic-equivalent deposited energy of similar to 15% above 10 TeV.
Abstract: Accurate measurement of neutrino energies is essential to many of the scientific goals of large-volume neutrino telescopes. The fundamental observable in such detectors is the Cherenkov light produced by the transit through a medium of charged particles created in neutrino interactions. The amount of light emitted is proportional to the deposited energy, which is approximately equal to the neutrino energy for v(e) and v(mu) charged-current interactions and can be used to set a lower bound on neutrino energies and to measure neutrino spectra statistically in other channels. Here we describe methods and performance of reconstructing charged-particle energies and topologies from the observed Cherenkov light yield, including techniques to measure the energies of uncontained muon tracks, achieving average uncertainties in electromagnetic-equivalent deposited energy of similar to 15% above 10 TeV.

Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2870 moreInstitutions (169)
01 Nov 2014
TL;DR: In this paper, the performance of ATLAS muon reconstruction during the LHC run with pp collisions at root s = 7-8 TeV in 2011-2012, focusing mainly on data collected in 2012.
Abstract: This paper presents the performance of the ATLAS muon reconstruction during the LHC run with pp collisions at root s = 7-8 TeV in 2011-2012, focusing mainly on data collected in 2012. Measurements ...

Journal ArticleDOI
TL;DR: In this article, the authors connect the resource-based view and its dynamic capability extension to introduce absorptive capacity (ACAP) as a moderator of the relationship between EO and firm performance.

Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek4  +2916 moreInstitutions (196)
01 Dec 2014
TL;DR: In this paper, a measurement of the production processes of the recently discovered Higgs boson is performed in the two-photon final state using 4.5 fb(-1) of proton-proton collisions data at root s = 7 TeV and 20.4 GeV.
Abstract: A measurement of the production processes of the recently discovered Higgs boson is performed in the two-photon final state using 4.5 fb(-1) of proton-proton collisions data at root s = 7 TeV and 20.3 fb(-1) at root s = 8 TeV collected by the ATLAS detector at the Large Hadron Collider. The number of observed Higgs boson decays to diphotons divided by the corresponding Standard Model prediction, called the signal strength, is found to be mu = 1.17 +/- 0.27 at the value of the Higgs boson mass measured by ATLAS, m(H) = 125.4 GeV. The analysis is optimized to measure the signal strengths for individual Higgs boson production processes at this value of m(H). They are found to be mu(ggF) = 1.32 +/- 0.38, mu(VBF) = 0.8 +/- 0.7, mu(WH) = 1.0 +/- 1.6, mu(ZH) = 0.1(-0.1)(+3.7), and mu t (t) over barH = 1.6(-1.8)(+2.7), for Higgs boson production through gluon fusion, vector-boson fusion, and in association with a W or Z boson or a top-quark pair, respectively. Compared with the previously published ATLAS analysis, the results reported here also benefit from a new energy calibration procedure for photons and the subsequent reduction of the systematic uncertainty on the diphoton mass resolution. No significant deviations from the predictions of the Standard Model are found.

Journal ArticleDOI
M. G. Aartsen1, Markus Ackermann, Jenni Adams2, Juanan Aguilar3  +306 moreInstitutions (42)
TL;DR: In this paper, the authors present results on searches for point-like sources of neutrinos using four years of IceCube data, including the first year of data from the completed 86 string detector.
Abstract: We present results on searches for point-like sources of neutrinos using four years of IceCube data, including the first year of data from the completed 86 string detector The total livetime of the combined data set is 1373 days For an E-2 spectrum, the observed 90% C L flux upper limits are similar to 10(-12) TeV-1 cm(-2) s(-1) for energies between 1 TeV and 1 PeV in the northern sky and similar to 10(-11) TeV-1 cm(-2) s(-1) for energies between 100 TeV and 100 PeV in the southern sky This represents a 40% improvement compared to previous publications, resulting from both the additional year of data and the introduction of improved reconstructions In addition, we present the first results from an all-sky search for extended sources of neutrinos We update the results of searches for neutrino emission from stacked catalogs of sources and test five new catalogs; two of Galactic supernova remnants and three of active galactic nuclei In all cases, the data are compatible with the background-only hypothesis, and upper limits on the flux of muon neutrinos are reported for the sources considered

Journal ArticleDOI
TL;DR: In this article, Debye devised a relaxation model for application to the dielectric properties of water and alcohols, which has been studied extensively because they are vital for biophysical processes, of fundamental importance as solvents in industrial processes and in every-day use.