| 1. |
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| 2. |
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| 3. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Manning, Alisa, et al.
(författare)
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A Low-Frequency Inactivating AKT2 Variant Enriched in the Finnish Population Is Associated With Fasting Insulin Levels and Type 2 Diabetes Risk
- 2017
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Ingår i: Diabetes. - : AMER DIABETES ASSOC. - 0012-1797 .- 1939-327X. ; 66:7, s. 2019-2032
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Tidskriftsartikel (refereegranskat)abstract
- To identify novel coding association signals and facilitate characterization of mechanisms influencing glycemic traits and type 2 diabetes risk, we analyzed 109,215 variants derived from exome array genotyping together with an additional 390,225 variants from exome sequence in up to 39,339 normoglycemic individuals from five ancestry groups. We identified a novel association between the coding variant (p.Pro50Thr) in AKT2 and fasting plasma insulin (FI), a gene in which rare fully penetrant mutations are causal for monogenic glycemic disorders. The low-frequency allele is associated with a 12% increase in FI levels. This variant is present at 1.1% frequency in Finns but virtually absent in individuals from other ancestries. Carriers of the FI-increasing allele had increased 2-h insulin values, decreased insulin sensitivity, and increased risk of type 2 diabetes (odds ratio 1.05). In cellular studies, the AKT2-Thr50 protein exhibited a partial loss of function. We extend the allelic spectrum for coding variants in AKT2 associated with disorders of glucose homeostasis and demonstrate bidirectional effects of variants within the pleckstrin homology domain of AKT2.
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| 5. |
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| 6. |
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| 7. |
- Ahluwalia, T. S., et al.
(författare)
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Genome-wide association study of circulating interleukin 6 levels identifies novel loci
- 2021
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Ingår i: Human molecular genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 30:5, s. 393-409
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin 6 (IL-6) is a multifunctional cytokine with both pro- and anti-inflammatory properties with a heritability estimate of up to 61%. The circulating levels of IL-6 in blood have been associated with an increased risk of complex disease pathogenesis. We conducted a two-staged, discovery and replication meta genome-wide association study (GWAS) of circulating serum IL-6 levels comprising up to 67428 (n(discovery)=52654 and n(replication)=14774) individuals of European ancestry. The inverse variance fixed effects based discovery meta-analysis, followed by replication led to the identification of two independent loci, IL1F10/IL1RN rs6734238 on chromosome (Chr) 2q14, (P-combined=1.8x10(-11)), HLA-DRB1/DRB5 rs660895 on Chr6p21 (P-combined=1.5x10(-10)) in the combined meta-analyses of all samples. We also replicated the IL6R rs4537545 locus on Chr1q21 (P-combined=1.2x10(-122)). Our study identifies novel loci for circulating IL-6 levels uncovering new immunological and inflammatory pathways that may influence IL-6 pathobiology.
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| 8. |
- Björk, Göran, 1956, et al.
(författare)
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Flow of Canadian Basin Deep Water in the Western Eurasian Basin of the Arctic Ocean
- 2010
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Ingår i: Deep Sea Research. - : Elsevier BV. - 0967-0637 .- 1879-0119. ; 57:4, s. 577-586
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Tidskriftsartikel (refereegranskat)abstract
- The LOMROG 2007 expedition targeted the previously unexplored southern part of the Lomonosov Ridge north of Greenland together with a section from the Morris Jesup Rise to Gakkel Ridge. The oceanographic data shows that Canadian Basin Deep Water (CBDW) passes the Lomonosov Ridge in the area of the Intra Basin close to the North Pole and then continues along the ridge towards Greenland and further along its northernmost continental slope. The CBDW is clearly evident as a salinity maximum and oxygen minimum at a depth of about 2000 m. The cross slope sections at the Amundsen Basin side of the Lomonosov Ridge and further south at the Morris Jesup Rise show a sharp frontal structure higher up in the water column between Makarov Basin water and Amundsen Basin water. The frontal structure continues upward into the Atlantic Water up to a depth of about 300 m. The observed water mass division at levels well above the ridge crest indicates a strong topographic steering of the flow and that different water masses tend to pass the ridge guided by ridge-crossing isobaths at local topographic heights and depressions. A rough scaling analysis shows that the extremely steep and sharply turning bathymetry of the Morris Jesup Rise may force the boundary current to separate and generate deep eddies.
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| 9. |
- Bombarda, F., et al.
(författare)
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Runaway electron beam control
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
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Tidskriftsartikel (refereegranskat)
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| 10. |
- Eriksson, Benjamin, et al.
(författare)
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Determining the fuel ion ratio for D(T)and T(D) plasmas at JET using neutron time-of-flight spectrometry
- 2022
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Ingår i: Plasma Physics and Controlled Fusion. - : Institute of Physics (IOP). - 0741-3335 .- 1361-6587. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- The fusion fuel ion ratio, nΤ/nD, is an important plasma parameter that needs to be tuned to maximize the power of a tokamak type fusion reactor. It is recognized as a parameter required for optimizing several ITER operating scenarios, and will likely be continuously monitored in future high-performance fusion devices such as DEMO. Tritium was recently introduced in the Joint European Torus (JET) plasma for the first time since the 1997 DTE1 and 2003 TTE campaigns, enabling the possibility to investigate fuel ion ratios. We present a method for measuring nΤ/nD using neutron time-of-flight (TOF) spectrometry. By fitting the measured neutron spectral features, the relative reaction rate intensities between different ion species can be inferred, from which the fuel ion ratio can be extracted for a corresponding modeled reactivity. Unlike previous measurements of nT/nD using neutron spectrometry, we utilize the neutron energy continuum produced in the three-body TT reaction to determine the fuel ion ratio for plasmas with large concentrations of tritium. Furthermore, the use of neutron TOF spectrometry has never previously been demonstrated for evaluating nT/nD. The method is applied to TOF spectra acquired with TOFOR (JET name KM11) and shown to be consistent with the optical JET diagnostic KT5P which uses optical spectroscopy of a modified Penning gauge plasma to measure tritium and deuterium concentrations in the divertor exhaust gas.
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| 11. |
- Eriksson, Benjamin, et al.
(författare)
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First measurement in a magnetic confinement fusion experiment of the T + T -> 5He + n intermediate two-body resonant reaction
- 2024
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 109
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Tidskriftsartikel (refereegranskat)abstract
- We report on the first experimental measurements made at a magnetic confinement fusion device of the T + T → α + 2n reaction indicating the presence of the intermediate two-body resonant reaction T + T → ⁵He + n. During the second deuterium-tritium campaign (DTE2) at the Joint European Torus, measurements of fusion plasmas with high tritium concentrations, n_T/(n_T + n_D) ≈ 0.99, heated with T neutral beam injection (NBI), were performed using the neutron time-of-flight (TOF) spectrometer TOFOR. We detect a peak in the neutron emission TOF spectrum consistent with the two-body resonant reaction. The TT neutron emission energy spectrum is modeled using an R-matrix framework where the distributions of the most likely model parameters given our experimental TOF data are determined utilizing a Markov chain Monte Carlo approach. We compare our best estimate of the TT neutron emission energy spectrum with results obtained at inertial confinement fusion experiments at the OMEGA facility and find a spectral shape that is consistent with the energy dependency in the neutron spectrum observed at OMEGA.
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| 12. |
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| 13. |
- Eriksson, Benjamin, et al.
(författare)
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New method for time alignment and time calibration of the TOFOR time-of-flight neutron spectrometer at JET
- 2021
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 92:3
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Tidskriftsartikel (refereegranskat)abstract
- The TOFOR time-of-flight (TOF) neutron spectrometer at the Joint European Torus (JET) is composed of 5 start (S1) and 32 stop (S2) scintillation detectors. Recently, the data acquisition system (DAQ) of TOFOR was upgraded to equip each of the 37 detectors with its own waveform digitizer to allow for correlated time and pulse height analysis of the acquired data. Due to varying cable lengths and different pulse processing pathways in the new DAQ system, the 160 (5.32) different TOF pairs of start-stop detectors must be time-aligned to enable the proper construction of a summed TOF spectrum. Given the time (energy) resolution required by the entire spectrometer system to measure different plasma neutron emission components, it is of importance to align the detector pairs to each other with sub-nanosecond precision. Previously, the alignment partially depended on using fusion neutron data from Ohmic heating phases of JET experimental pulses. The dependence on fusion neutron data in the time alignment process is, however, unsatisfactory as it involves data one would wish to include in an independent analysis for physics results. In this work, we describe a method of time-aligning the detector pairs by using gamma rays. Given the known geometry and response of TOFOR to gamma rays, the time alignment of the detector pairs is found by examining gamma events interacting in coincidence in both S1-S1 and S1-S2 detector combinations. Furthermore, a technique for separating neutron and gamma events in the different detector sets is presented. Finally, the time-aligned system is used to analyze neutron data from Ohmic phases for different plasma conditions and to estimate the Ohmic fuel ion temperature.
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| 14. |
- Eriksson, Benjamin, 1992-
(författare)
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The evolution of TOFu : Developing and utilizing neutron time-of-flight spectrometry of deuterium and tritium fusion plasmas at JET
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Considerable effort has been invested in attempting to generate electricity from the energy released in controlled thermonuclear fusion reactions, with a European fusion research roadmap stretching beyond 2050. Our current endeavors may culminate in a virtually inexhaustible, low-carbon energy source for future generations. Experimental reactors such as the Joint European Torus (JET) and the International Thermonuclear Experimental Reactor (ITER) are stepping stones on the road to demonstrating the viability of fusion energy. Using various diagnostics and simulations, information on the plasma conditions in such experimental reactors can be obtained.In this thesis, the neutron time-of-flight spectrometer TOFOR at JET is used to study the neutron emission spectrum from the JET machine to determine different fusion plasma parameters. The first part of the thesis describes the efforts to upgrade the data acquisition (DAQ) system of TOFOR with a new, fully digital system: TOFu. Data reduction techniques are developed for the new DAQ system, and are shown to increase the signal-to-background ratio significantly. The instrumental response function is improved using the new system by measuring the energy-dependent time resolution and energy thresholds and applying them to the response function. Data analysis routines are developed to generate time-of-flight spectra from the data acquired by the 37 TOFOR sub-detectors.In the second part of the thesis, the data acquired by the new DAQ system is used to perform various physics studies of JET plasmas. We demonstrate the possibility of measuring the fuel ion temperature for Ohmic discharges of pure deuterium plasmas, with a precision that was unattainable with the former DAQ system. Furthermore, during the time of my doctoral studies, two deuterium-tritium experimental campaigns (DTE2 and DTE3) were conducted at JET. In order to contribute to the analysis of these experiments, we developed methods to measure the tritium fuel concentration in the fusion plasma using TOFOR. Also, experiments with pure tritium plasmas gave us the unique opportunity to measure the neutron emission spectrum from the T + T4He + 2n reaction during which we made the first observation in a magnetically confined plasma of the intermediate resonant reaction T + T5He + n.The analysis methods and experimental techniques developed in this thesis may be used in future neutron spectrometry systems, e.g., at ITER where there are plans to build a high-resolution neutron spectrometer (HRNS) consisting of several detection systems, one of which is a TOFOR-like time-of-flight spectrometer.
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| 15. |
- Eriksson, Benjamin, et al.
(författare)
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TOFu : A fully digital data acquisition system upgrade for the neutron time-of-flight spectrometer TOFOR
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 1049
-
Tidskriftsartikel (refereegranskat)abstract
- TOFOR is a time-of-flight (TOF) neutron spectrometer located at the Joint European Torus (JET) with a vertical sightline of the JET plasma. It consists of 5 start (denoted S1) and 32 stop (denoted S2) plastic scintillation detectors which can be used in coincidence to generate a TOF spectrum. Spectroscopic analysis of the neutron TOF spectra produced by the JET plasma is regularly performed to determine, e.g., the fuel ion ratio and the presence of fast ion species in the fusion plasma. TOFOR has been upgraded with a new digital data acquisition (DAQ) system, denoted TOFu, which consists of 10 waveform digitizers with a total of 40 channels, 37 of which are connected to the photomultiplier output of the different S1 and S2 detectors. This paper presents a technical overview of the TOFu system and describes the offline analysis capabilities of TOFu which were not available with the previous DAQ system. Two experimental JET discharges are studied and used to show that the signal-to-background ratio is improved by almost 200% for the 2.5 MeV neutron signal and almost 400% for the 14 MeV neutron signal using the new offline analysis capabilities.
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| 16. |
- Furmark, Tomas, et al.
(författare)
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Guided and unguided self-help for social anxiety disorder : randomised controlled trial
- 2009
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Ingår i: British Journal of Psychiatry. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 195:5, s. 440-447
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Tidskriftsartikel (refereegranskat)abstract
- Background Internet-delivered self-help programmes with added guidance have shown efficacy in social anxiety disorder, unguided self-help has been insufficiently studied. Aims To evaluate the efficacy of guided and unguided self-help social anxiety disorder. Method Participants followed a cognitive-behavioural self-help programme in the form of either pure bibliotherapy or an internet-based treatment with therapist guidance and online group discussions. A subsequent trial was conducted to evaluate treatment specificity. Participants (n=235) were randomised to one of three conditions in the first trial, or one of four conditions in the second. Results Pure bibliotherapy and the internet-based treatment were better than waiting list on measures of social anxiety, general anxiety, depression and quality of life. The internet-based therapy had the highest effect sizes, but directly comparable effects were noted for bibliotherapy augmented with online group discussions. Gains were well maintained a year later. Conclusions Unguided self-help through bibliotherapy can produce enduring improvement for individuals with social anxiety disorder.
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| 17. |
- Hobirk, J., et al.
(författare)
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The JET hybrid scenario in Deuterium, Tritium and Deuterium-Tritium
- 2023
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Ingår i: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 63:11
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Tidskriftsartikel (refereegranskat)abstract
- The JET hybrid scenario has been developed from low plasma current carbon wall discharges to the record-breaking Deuterium-Tritium plasmas obtained in 2021 with the ITER-like Be/W wall. The development started in pure Deuterium with refinement of the plasma current, and toroidal magnetic field choices and succeeded in solving the heat load challenges arising from 37 MW of injected power in the ITER like wall environment, keeping the radiation in the edge and core controlled, avoiding MHD instabilities and reaching high neutron rates. The Deuterium hybrid plasmas have been re-run in Tritium and methods have been found to keep the radiation controlled but not at high fusion performance probably due to time constraints. For the first time this scenario has been run in Deuterium-Tritium (50:50). These plasmas were re-optimised to have a radiation-stable H-mode entry phase, good impurity control through edge Ti gradient screening and optimised performance with fusion power exceeding 10 MW for longer than three alpha particle slow down times, 8.3 MW averaged over 5 s and fusion energy of 45.8 MJ.
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| 18. |
- Joshi, Peter K, et al.
(författare)
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Directional dominance on stature and cognition in diverse human populations
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523:7561, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.
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| 19. |
- Lundblad, Benjamin, 1994, et al.
(författare)
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Black Ostrich: Web Application Scanning with String Solvers
- 2023
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Ingår i: CCS 2023 - Proceedings of the 2023 ACM SIGSAC Conference on Computer and Communications Security. - : Association for Computing Machinery (ACM). ; , s. 549-563, s. 549-563
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Konferensbidrag (refereegranskat)abstract
- Securing web applications remains a pressing challenge. Unfortunately, the state of the art in web crawling and security scanning still falls short of deep crawling. A major roadblock is the crawlers' limited ability to pass input validation checks when web applications require data of a certain format, such as email, phone number, or zip code. This paper develops Black Ostrich, a principled approach to deep web crawling and scanning. The key idea is to equip web crawling with string constraint solving capabilities to dynamically infer suitable inputs from regular expression patterns in web applications and thereby pass input validation checks. To enable this use of constraint solvers, we develop new automata-based techniques to process JavaScript regular expressions. We implement our approach extending and combining the Ostrich constraint solver with the Black Widow web crawler. We evaluate Black Ostrich on a set of 8,820 unique validation patterns gathered from over 21,667,978 forms from a combination of the July 2021 Common Crawl and Tranco top 100K. For these forms and reconstructions of input elements corresponding to the patterns, we demonstrate that Black Ostrich achieves a 99% coverage of the form validations compared to an average of 36% for the state-of-the-art scanners. Moreover, out of the 66,377 domains using these patterns, we solve all patterns on 66,309 (99%) while the combined efforts of the other scanners cover 52,632 (79%). We further show that our approach can boost coverage by evaluating it on three open-source applications. Our empirical studies include a study of email validation patterns, where we find that 213 (26%) out of the 825 found email validation patterns liberally admit XSS injection payloads.
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| 20. |
- Marcinkevicius, Benjaminas, et al.
(författare)
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Fuel ion ratio determination using the 14 MeV Tandem neutron spectrometer for JET DTE1 campaign discharges
- 2022
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Ingår i: Fusion engineering and design. - : Elsevier. - 0920-3796 .- 1873-7196. ; 184
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the determination of the fuel ion ratio nT/ntot in fusion experiments using two different approaches. The methods are applied to plasma discharges from the deuterium-tritium campaign at the Joint European Torus (JET) in 1997. Multiple discharges have been analysed using data acquired with the Tandem (KM2) neutron spectrometer, using a new neutron spectrometer response function and improved line-of-sight information.The two different approaches were generally similar with the exception of the beam slowing down modelling, handled by two different particle transport codes, namely, TRANSP and PENCIL.The results show that nT/ntot can be determined using Tandem neutron spectrometer data; nT/ntot using both of the approaches are consistent and within the uncertainty for a range of studied discharges.The obtained results support previous studies on nT/ntot determination using neutron spectroscopy. In addition, we have shown that PENCIL can be used instead of TRANSP for a range of discharges which could simplify and speed up the estimation of nT/ntot. The possible limitations of the approach using PENCIL could be investigated using different neutron spectrometer data from the 2021 JET deuterium-tritium campaign.A similar spectrometer like Tandem is planned to be operational at ITER and the results of this paper form the first experimental verification of the capability for nT/ntot measurements with such spectrometers. Further research on this could lead to better understanding of these instruments and their limitations before the start of experiments at ITER.
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| 21. |
- Sahlberg, Arne, et al.
(författare)
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Analysis of the neutron spectrum from T+T reactions in NBI-heated fusion plasmas at JET
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In tritium (T) plasma experiments at the tokamak JET, the neutron emission spectrum has been measured with the time-of-flight spectrometer TOFOR and analyzed to determine the probability for the short-lived 5He resonance occurring in T+T reactions. Using a component-based model of the neutron emission from the T+T and D+T reactions present in a tritium plasma at JET, with trace deuterium, and fitting said model to the measured time-of-flight spectrum, we estimate the branching ratio for the different T+T reactions.From an analysis of TOFOR data from 33 NBI-heated tritium discharges, we learn that the ground state 5He-resonance occurs in 5.8(15)% of the T+T reactions at COM energies in the range 50-100 keV. These results fall in line with previous most measurements done at particle accelerators and inertial confinement fusion reactors.Apart from providing increased insight into the physics of the T+T reaction, the value of the branching ratio obtained in this study can lead to improved models of the neutron emission spectrum from tokamaks, and aid in the interpretation of neutron measurements from future T and DT experiments.
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| 22. |
- Aad, G., et al.
(författare)
-
- 2014
-
Tidskriftsartikel (refereegranskat)
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| 23. |
- Aad, G., et al.
(författare)
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- 2011
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Tidskriftsartikel (refereegranskat)
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| 24. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 25. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :9
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Tidskriftsartikel (refereegranskat)
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| 26. |
- Aad, G., et al.
(författare)
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- 2013
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; :10
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Tidskriftsartikel (refereegranskat)
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| 27. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 90:11
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Tidskriftsartikel (refereegranskat)
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| 28. |
- Aad, G., et al.
(författare)
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- 2014
-
Tidskriftsartikel (refereegranskat)
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| 29. |
- Aad, G., et al.
(författare)
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- 2015
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Tidskriftsartikel (refereegranskat)
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| 30. |
-
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:9
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Tidskriftsartikel (refereegranskat)
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| 31. |
-
- 2018
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 58:1
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Forskningsöversikt (refereegranskat)
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| 32. |
- Aad, G., et al.
(författare)
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Commissioning of the ATLAS Muon Spectrometer with cosmic rays
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 875-916
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.
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| 33. |
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| 34. |
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| 35. |
- Aad, G, et al.
(författare)
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Observation and measurements of the production of prompt and non-prompt [Formula: see text] mesons in association with a [Formula: see text] boson in [Formula: see text] collisions at [Formula: see text] with the ATLAS detector.
- 2015
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 75:5
-
Tidskriftsartikel (refereegranskat)abstract
- The production of a [Formula: see text] boson in association with a [Formula: see text] meson in proton-proton collisions probes the production mechanisms of quarkonium and heavy flavour in association with vector bosons, and allows studies of multiple parton scattering. Using [Formula: see text] of data collected with the ATLAS experiment at the LHC in [Formula: see text] collisions at [Formula: see text], the first measurement of associated [Formula: see text] production is presented for both prompt and non-prompt [Formula: see text] production, with both signatures having a significance in excess of [Formula: see text]. The inclusive production cross-sections for [Formula: see text] boson production (analysed in [Formula: see text] or [Formula: see text] decay modes) in association with prompt and non-prompt [Formula: see text] are measured relative to the inclusive production rate of [Formula: see text] bosons in the same fiducial volume to be [Formula: see text] and [Formula: see text] respectively. Normalised differential production cross-section ratios are also determined as a function of the [Formula: see text] transverse momentum. The fraction of signal events arising from single and double parton scattering is estimated, and a lower limit of [Formula: see text] at [Formula: see text] confidence level is placed on the effective cross-section regulating double parton interactions.
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| 36. |
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| 37. |
- Aad, G., et al.
(författare)
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Readiness of the ATLAS Tile Calorimeter for LHC collisions
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:4, s. 1193-1236
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Tidskriftsartikel (refereegranskat)abstract
- The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector has successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration systems are presented, as well as the validation of the timing and energy calibration carried out with minimum ionising cosmic ray muons data. The calibration systems' precision is well below the design value of 1%. The determination of the global energy scale was performed with an uncertainty of 4%.
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| 38. |
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| 39. |
- Aad, G, et al.
(författare)
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Search for direct pair production of a chargino and a neutralino decaying to the 125 GeV Higgs boson in [Formula: see text] TeV [Formula: see text] collisions with the ATLAS detector.
- 2015
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 75:5
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Tidskriftsartikel (refereegranskat)abstract
- A search is presented for the direct pair production of a chargino and a neutralino [Formula: see text], where the chargino decays to the lightest neutralino and the [Formula: see text] boson, [Formula: see text], while the neutralino decays to the lightest neutralino and the 125 GeV Higgs boson, [Formula: see text]. The final states considered for the search have large missing transverse momentum, an isolated electron or muon, and one of the following: either two jets identified as originating from bottom quarks, or two photons, or a second electron or muon with the same electric charge. The analysis is based on 20.3 [Formula: see text] of [Formula: see text] proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations, and limits are set in the context of a simplified supersymmetric model.
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| 40. |
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| 41. |
- Aad, G, et al.
(författare)
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Search for Higgs Boson Pair Production in the γγbb[over ¯] Final State Using pp Collision Data at sqrt[s]=8 TeV from the ATLAS Detector.
- 2015
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Ingår i: Physical Review Letters. - 1079-7114. ; 114:8
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Tidskriftsartikel (refereegranskat)abstract
- Searches are performed for resonant and nonresonant Higgs boson pair production in the γγbb[over ¯] final state using 20 fb^{-1} of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the CERN Large Hadron Collider. A 95% confidence level upper limit on the cross section times branching ratio of nonresonant production is set at 2.2 pb, while the expected limit is 1.0 pb. The difference derives from a modest excess of events, corresponding to 2.4 standard deviations from the background-only hypothesis. The limit observed in the search for a narrow X→hh resonance ranges between 0.7 and 3.5 pb as a function of the resonance mass.
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| 42. |
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| 43. |
- Aad, G, et al.
(författare)
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Search for production of [Formula: see text] resonances decaying to a lepton, neutrino and jets in [Formula: see text] collisions at [Formula: see text] TeV with the ATLAS detector.
- 2015
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 75:5
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Tidskriftsartikel (refereegranskat)abstract
- A search is presented for narrow diboson resonances decaying to [Formula: see text] or [Formula: see text] in the final state where one [Formula: see text] boson decays leptonically (to an electron or a muon plus a neutrino) and the other [Formula: see text] boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb[Formula: see text] of [Formula: see text] collisions at [Formula: see text] TeV collected by the ATLAS detector at the large hadron collider. No evidence for resonant diboson production is observed, and resonance masses below 700 and 1490 GeV are excluded at 95 % confidence level for the spin-2 Randall-Sundrum bulk graviton [Formula: see text] with coupling constant of 1.0 and the extended gauge model [Formula: see text] boson respectively.
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| 44. |
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| 45. |
- Aad, G., et al.
(författare)
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Studies of the performance of the ATLAS detector using cosmic-ray muons
- 2011
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:3
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Tidskriftsartikel (refereegranskat)abstract
- Muons from cosmic-ray interactions in the atmosphere provide a high-statistics source of particles that can be used to study the performance and calibration of the ATLAS detector. Cosmic-ray muons can penetrate to the cavern and deposit energy in all detector subsystems. Such events have played an important role in the commissioning of the detector since the start of the installation phase in 2005 and were particularly important for understanding the detector performance in the time prior to the arrival of the first LHC beams. Global cosmic-ray runs were undertaken in both 2008 and 2009 and these data have been used through to the early phases of collision data-taking as a tool for calibration, alignment and detector monitoring. These large datasets have also been used for detector performance studies, including investigations that rely on the combined performance of different subsystems. This paper presents the results of performance studies related to combined tracking, lepton identification and the reconstruction of jets and missing transverse energy. Results are compared to expectations based on a cosmic-ray event generator and a full simulation of the detector response.
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| 46. |
- Aad, G., et al.
(författare)
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The ATLAS Inner Detector commissioning and calibration
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 787-821
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
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| 47. |
- Aad, G., et al.
(författare)
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The ATLAS Simulation Infrastructure
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 823-874
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Tidskriftsartikel (refereegranskat)abstract
- The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.
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| 48. |
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| 49. |
- Abata, E., et al.
(författare)
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Study of energy response and resolution of the ATLAS barrel calorimeter to hadrons of energies from 20 to 350 GeV
- 2010
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 621:1-3, s. 134-150
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Tidskriftsartikel (refereegranskat)abstract
- A fully instrumented slice of the ATLAS detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the results of the measurements of the response of the barrel calorimeter to hadrons with energies in the range 20-350 GeV and beam impact points and angles corresponding to pseudo-rapidity values in the range 0.2-0.65 are reported. The results are compared to the predictions of a simulation program using the Geant 4 toolkit. (C) 2010 Published by Elsevier B.V.
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| 50. |
- Abou-Taouk, Abdallah, 1982, et al.
(författare)
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Optimized Reduced Chemistry and Molecular Transport for Large Eddy Simulation of Partially Premixed Combustion in a Gas Turbine
- 2016
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Ingår i: Combustion Science and Technology. - : Informa UK Limited. - 0010-2202 .- 1563-521X. ; 188:1, s. 21-39
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Tidskriftsartikel (refereegranskat)abstract
- A methodology is discussed to automatically determine the parameters of closed budget equations for chemical species mass fractions and energy, in order to simulate spatially filtered flames as required in large eddy simulation (LES). The method accounts for the effects of LES filtering on chemistry and transport by simultaneously optimizing, for a reduced number of species, the Arrhenius reaction rates and a correction to mixture-averaged molecular diffusion coefficients. The objective is to match, for a given filter size, spatially filtered canonical one-dimensional flames simulated with detailed chemistry solutions. This approach is designed for quite well-resolved LES, in which most of the unresolved fluctuations result from flame thickening due to spatial filtering, thus featuring weak levels of sub-grid scale flame wrinkling. Methane-air partially premixed combustion is addressed. A four-step reduced reaction mechanism involving seven species is developed along with mass and heat molecular transport properties. The optimization is performed at atmospheric pressure and at 3 bar, for ranges of fresh gas temperatures [300–650 K] and equivalence ratios [0.4–1.2]. Comparisons with the filtered detailed chemistry solution of a planar propagating front show that the laminar flame speed, the adiabatic flame temperature, the species profiles in the reaction zone, and the flow chemical composition and temperature at equilibrium are adequately predicted. The new sub-grid scale modeling approach is then applied to three-dimensional LES of an industrial gas turbine burner. Good agreement is found between the quantities predicted with LES and experimental data, in terms of flow and flame dynamics, axial velocities, averaged temperatures, and some major species concentrations. Results are also improved compared to previous simulations of the same burner.
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