| 1. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 2. |
- Kanoni, Stavroula, et al.
(författare)
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Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis.
- 2022
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Ingår i: Genome biology. - : Springer Science and Business Media LLC. - 1474-760X .- 1465-6906 .- 1474-7596. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery.To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N=1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3-5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism.Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.
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| 3. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 4. |
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The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data
- 2022
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Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
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| 5. |
- Schweinsberg, Martin, et al.
(författare)
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Same data, different conclusions : Radical dispersion in empirical results when independent analysts operationalize and test the same hypothesis
- 2021
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Ingår i: Organizational Behavior and Human Decision Processes. - : Elsevier BV. - 0749-5978 .- 1095-9920. ; 165, s. 228-249
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Tidskriftsartikel (refereegranskat)abstract
- In this crowdsourced initiative, independent analysts used the same dataset to test two hypotheses regarding the effects of scientists' gender and professional status on verbosity during group meetings. Not only the analytic approach but also the operationalizations of key variables were left unconstrained and up to individual analysts. For instance, analysts could choose to operationalize status as job title, institutional ranking, citation counts, or some combination. To maximize transparency regarding the process by which analytic choices are made, the analysts used a platform we developed called DataExplained to justify both preferred and rejected analytic paths in real time. Analyses lacking sufficient detail, reproducible code, or with statistical errors were excluded, resulting in 29 analyses in the final sample. Researchers reported radically different analyses and dispersed empirical outcomes, in a number of cases obtaining significant effects in opposite directions for the same research question. A Boba multiverse analysis demonstrates that decisions about how to operationalize variables explain variability in outcomes above and beyond statistical choices (e.g., covariates). Subjective researcher decisions play a critical role in driving the reported empirical results, underscoring the need for open data, systematic robustness checks, and transparency regarding both analytic paths taken and not taken. Implications for orga-nizations and leaders, whose decision making relies in part on scientific findings, consulting reports, and internal analyses by data scientists, are discussed.
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| 6. |
- de las Fuentes, Lisa, et al.
(författare)
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Gene-educational attainment interactions in a multi-ancestry genome-wide meta-analysis identify novel blood pressure loci
- 2021
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Ingår i: Molecular Psychiatry. - : Springer Nature. - 1359-4184 .- 1476-5578. ; 26:6, s. 2111-2125
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Tidskriftsartikel (refereegranskat)abstract
- Educational attainment is widely used as a surrogate for socioeconomic status (SES). Low SES is a risk factor for hypertension and high blood pressure (BP). To identify novel BP loci, we performed multi-ancestry meta-analyses accounting for gene-educational attainment interactions using two variables, “Some College” (yes/no) and “Graduated College” (yes/no). Interactions were evaluated using both a 1 degree of freedom (DF) interaction term and a 2DF joint test of genetic and interaction effects. Analyses were performed for systolic BP, diastolic BP, mean arterial pressure, and pulse pressure. We pursued genome-wide interrogation in Stage 1 studies (N = 117 438) and follow-up on promising variants in Stage 2 studies (N = 293 787) in five ancestry groups. Through combined meta-analyses of Stages 1 and 2, we identified 84 known and 18 novel BP loci at genome-wide significance level (P < 5 × 10-8). Two novel loci were identified based on the 1DF test of interaction with educational attainment, while the remaining 16 loci were identified through the 2DF joint test of genetic and interaction effects. Ten novel loci were identified in individuals of African ancestry. Several novel loci show strong biological plausibility since they involve physiologic systems implicated in BP regulation. They include genes involved in the central nervous system-adrenal signaling axis (ZDHHC17, CADPS, PIK3C2G), vascular structure and function (GNB3, CDON), and renal function (HAS2 and HAS2-AS1, SLIT3). Collectively, these findings suggest a role of educational attainment or SES in further dissection of the genetic architecture of BP.
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| 7. |
- Reinke, Beth A, et al.
(författare)
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Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 376:6600, s. 1459-1466
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Tidskriftsartikel (refereegranskat)abstract
- Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.
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| 8. |
- Micah, Angela E., et al.
(författare)
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Tracking development assistance for health and for COVID-19 : a review of development assistance, government, out-of-pocket, and other private spending on health for 204 countries and territories, 1990-2050
- 2021
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Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 398:10308, s. 1317-1343
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Forskningsöversikt (refereegranskat)abstract
- Background The rapid spread of COVID-19 renewed the focus on how health systems across the globe are financed, especially during public health emergencies. Development assistance is an important source of health financing in many low-income countries, yet little is known about how much of this funding was disbursed for COVID-19. We aimed to put development assistance for health for COVID-19 in the context of broader trends in global health financing, and to estimate total health spending from 1995 to 2050 and development assistance for COVID-19 in 2020. Methods We estimated domestic health spending and development assistance for health to generate total health-sector spending estimates for 204 countries and territories. We leveraged data from the WHO Global Health Expenditure Database to produce estimates of domestic health spending. To generate estimates for development assistance for health, we relied on project-level disbursement data from the major international development agencies' online databases and annual financial statements and reports for information on income sources. To adjust our estimates for 2020 to include disbursements related to COVID-19, we extracted project data on commitments and disbursements from a broader set of databases (because not all of the data sources used to estimate the historical series extend to 2020), including the UN Office of Humanitarian Assistance Financial Tracking Service and the International Aid Transparency Initiative. We reported all the historic and future spending estimates in inflation-adjusted 2020 US$, 2020 US$ per capita, purchasing-power parity-adjusted US$ per capita, and as a proportion of gross domestic product. We used various models to generate future health spending to 2050. Findings In 2019, health spending globally reached $8. 8 trillion (95% uncertainty interval [UI] 8.7-8.8) or $1132 (1119-1143) per person. Spending on health varied within and across income groups and geographical regions. Of this total, $40.4 billion (0.5%, 95% UI 0.5-0.5) was development assistance for health provided to low-income and middle-income countries, which made up 24.6% (UI 24.0-25.1) of total spending in low-income countries. We estimate that $54.8 billion in development assistance for health was disbursed in 2020. Of this, $13.7 billion was targeted toward the COVID-19 health response. $12.3 billion was newly committed and $1.4 billion was repurposed from existing health projects. $3.1 billion (22.4%) of the funds focused on country-level coordination and $2.4 billion (17.9%) was for supply chain and logistics. Only $714.4 million (7.7%) of COVID-19 development assistance for health went to Latin America, despite this region reporting 34.3% of total recorded COVID-19 deaths in low-income or middle-income countries in 2020. Spending on health is expected to rise to $1519 (1448-1591) per person in 2050, although spending across countries is expected to remain varied. Interpretation Global health spending is expected to continue to grow, but remain unequally distributed between countries. We estimate that development organisations substantially increased the amount of development assistance for health provided in 2020. Continued efforts are needed to raise sufficient resources to mitigate the pandemic for the most vulnerable, and to help curtail the pandemic for all. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.
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| 9. |
- Baxter, Amanda L., et al.
(författare)
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Collaborative experience between scientific software projects using Agile Scrum development
- 2022
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Ingår i: Software, practice & experience. - : John Wiley & Sons. - 0038-0644 .- 1097-024X. ; 52:10, s. 2077-2096
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Tidskriftsartikel (refereegranskat)abstract
- Developing sustainable software for the scientific community requires expertise in software engineering and domain science. This can be challenging due to the unique needs of scientific software, the insufficient resources for software engineering practices in the scientific community, and the complexity of developing for evolving scientific contexts. While open-source software can partially address these concerns, it can introduce complicating dependencies and delay development. These issues can be reduced if scientists and software developers collaborate. We present a case study wherein scientists from the SuperNova Early Warning System collaborated with software developers from the Scalable Cyberinfrastructure for Multi-Messenger Astrophysics project. The collaboration addressed the difficulties of open-source software development, but presented additional risks to each team. For the scientists, there was a concern of relying on external systems and lacking control in the development process. For the developers, there was a risk in supporting a user-group while maintaining core development. These issues were mitigated by creating a second Agile Scrum framework in parallel with the developers' ongoing Agile Scrum process. This Agile collaboration promoted communication, ensured that the scientists had an active role in development, and allowed the developers to evaluate and implement the scientists' software requirements. The collaboration provided benefits for each group: the scientists actuated their development by using an existing platform, and the developers utilized the scientists' use-case to improve their systems. This case study suggests that scientists and software developers can avoid scientific computing issues by collaborating and that Agile Scrum methods can address emergent concerns.
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| 10. |
- Ntalla, Ioanna, et al.
(författare)
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Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N=293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.5% to 62.6%. We observe enrichment for cardiac muscle developmental/contractile and cytoskeletal genes, highlighting key regulation processes for atrioventricular conduction. Additionally, 8 loci not previously reported harbor genes underlying inherited arrhythmic syndromes and/or cardiomyopathies suggesting a role for these genes in cardiovascular pathology in the general population. We show that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease, including distal conduction disease, AF, and atrioventricular pre-excitation. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease. On the electrocardiogram, the PR interval reflects conduction from the atria to ventricles and also serves as risk indicator of cardiovascular morbidity and mortality. Here, the authors perform genome-wide meta-analyses for PR interval in multiple ancestries and identify 141 previously unreported genetic loci.
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| 11. |
- Palmer, Duncan S., et al.
(författare)
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Exome sequencing in bipolar disorder identifies AKAP11 as a risk gene shared with schizophrenia
- 2022
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 54:5, s. 541-547
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Tidskriftsartikel (refereegranskat)abstract
- We report results from the Bipolar Exome (BipEx) collaboration analysis of whole-exome sequencing of 13,933 patients with bipolar disorder (BD) matched with 14,422 controls. We find an excess of ultra-rare protein-truncating variants (PTVs) in patients with BD among genes under strong evolutionary constraint in both major BD subtypes. We find enrichment of ultra-rare PTVs within genes implicated from a recent schizophrenia exome meta-analysis (SCHEMA; 24,248 cases and 97,322 controls) and among binding targets of CHD8. Genes implicated from genome-wide association studies (GWASs) of BD, however, are not significantly enriched for ultra-rare PTVs. Combining gene-level results with SCHEMA, AKAP11 emerges as a definitive risk gene (odds ratio (OR) = 7.06, P = 2.83 × 10−9). At the protein level, AKAP-11 interacts with GSK3B, the hypothesized target of lithium, a primary treatment for BD. Our results lend support to BD’s polygenicity, demonstrating a role for rare coding variation as a significant risk factor in BD etiology.
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| 12. |
- Åkerlund, Cecilia, 1983-, et al.
(författare)
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Clustering identifies endotypes of traumatic brain injury in an intensive care cohort : a CENTER-TBI study
- 2022
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Ingår i: Critical Care. - : BioMed Central (BMC). - 1364-8535 .- 1466-609X. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: While the Glasgow coma scale (GCS) is one of the strongest outcome predictors, the current classification of traumatic brain injury (TBI) as 'mild', 'moderate' or 'severe' based on this fails to capture enormous heterogeneity in pathophysiology and treatment response. We hypothesized that data-driven characterization of TBI could identify distinct endotypes and give mechanistic insights.METHODS: We developed an unsupervised statistical clustering model based on a mixture of probabilistic graphs for presentation (< 24 h) demographic, clinical, physiological, laboratory and imaging data to identify subgroups of TBI patients admitted to the intensive care unit in the CENTER-TBI dataset (N = 1,728). A cluster similarity index was used for robust determination of optimal cluster number. Mutual information was used to quantify feature importance and for cluster interpretation.RESULTS: Six stable endotypes were identified with distinct GCS and composite systemic metabolic stress profiles, distinguished by GCS, blood lactate, oxygen saturation, serum creatinine, glucose, base excess, pH, arterial partial pressure of carbon dioxide, and body temperature. Notably, a cluster with 'moderate' TBI (by traditional classification) and deranged metabolic profile, had a worse outcome than a cluster with 'severe' GCS and a normal metabolic profile. Addition of cluster labels significantly improved the prognostic precision of the IMPACT (International Mission for Prognosis and Analysis of Clinical trials in TBI) extended model, for prediction of both unfavourable outcome and mortality (both p < 0.001).CONCLUSIONS: Six stable and clinically distinct TBI endotypes were identified by probabilistic unsupervised clustering. In addition to presenting neurology, a profile of biochemical derangement was found to be an important distinguishing feature that was both biologically plausible and associated with outcome. Our work motivates refining current TBI classifications with factors describing metabolic stress. Such data-driven clusters suggest TBI endotypes that merit investigation to identify bespoke treatment strategies to improve care.
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| 13. |
- Aad, G, et al.
(författare)
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Alignment of the ATLAS Inner Detector in Run 2
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:12
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Tidskriftsartikel (refereegranskat)abstract
- The performance of the ATLAS Inner Detector alignment has been studied using pp collision data at s=13TeV collected by the ATLAS experiment during Run 2 (2015–2018) of the Large Hadron Collider (LHC). The goal of the detector alignment is to determine the detector geometry as accurately as possible and correct for time-dependent movements. The Inner Detector alignment is based on the minimization of track-hit residuals in a sequence of hierarchical levels, from global mechanical assembly structures to local sensors. Subsequent levels have increasing numbers of degrees of freedom; in total there are almost 750,000. The alignment determines detector geometry on both short and long timescales, where short timescales describe movements within an LHC fill. The performance and possible track parameter biases originating from systematic detector deformations are evaluated. Momentum biases are studied using resonances decaying to muons or to electrons. The residual sagitta bias and momentum scale bias after alignment are reduced to less than ∼0.1TeV-1 and 0.9 × 10 - 3, respectively. Impact parameter biases are also evaluated using tracks within jets. © 2020, The Author(s).
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| 14. |
- Aad, G., et al.
(författare)
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Emulating the impact of additional proton–proton interactions in the ATLAS simulation by presampling sets of inelastic Monte Carlo events
- 2022
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Ingår i: Computing and Software for Big Science. - : Springer Science and Business Media LLC. - 2510-2044 .- 2510-2036. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
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| 15. |
- Aad, G, et al.
(författare)
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Exclusive dimuon production in ultraperipheral Pb + Pb collisions at √sNN= 5.02 TeV with ATLAS
- 2021
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 104:2
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Tidskriftsartikel (refereegranskat)abstract
- Exclusive dimuon production in ultraperipheral collisions (UPC), resulting from photon-photon interactions in the strong electromagnetic fields of colliding high-energy lead nuclei, PbPb(γγ) → μ+μ-(Pb(∗)Pb(∗)), is studied using Lint = 0.48 nb-1 of √sNN = 5.02 TeV lead-lead collision data at the LHC with the ATLAS detector. Dimuon pairs are measured in the fiducial region pT,μ > 4 GeV, |ημ| <2.4, invariant mass mμμ > 10 GeV, and pT,μμ <2 GeV. The primary background from single-dissociative processes is extracted from the data using a template fitting technique. Differential cross sections are presented as a function of mμμ, absolute pair rapidity (|yμμ|), scattering angle in the dimuon rest frame (|cos $μμ∗|), and the colliding photon energies. The total cross section of the UPC γγ → μ+μ- process in the fiducial volume is measured to be σfidμμ = 34.1±0.3(stat.)±0.7(syst.) μb. Generally good agreement is found with calculations from STARlight, which incorporate the leading-order Breit-Wheeler process with no final-state effects, albeit differences between the measurements and theoretical expectations are observed. In particular, the measured cross sections at larger |yμμ| are found to be about 10-20% larger in data than in the calculations, suggesting the presence of larger fluxes of photons in the initial state. Modification of the dimuon cross sections in the presence of forward and/or backward neutron production is also studied and is found to be associated with a harder incoming photon spectrum, consistent with expectations. © 2021 CERN.
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| 16. |
- Aad, G, et al.
(författare)
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Jet energy scale and resolution measured in proton–proton collisions at √s=13 TeV with the ATLAS detector
- 2021
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:8
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Tidskriftsartikel (refereegranskat)abstract
- Jet energy scale and resolution measurements with their associated uncertainties are reported for jets using 36–81 fb−1 of proton–proton collision data with a centre-of-mass energy of s√=13 TeV collected by the ATLAS detector at the LHC. Jets are reconstructed using two different input types: topo-clusters formed from energy deposits in calorimeter cells, as well as an algorithmic combination of charged-particle tracks with those topo-clusters, referred to as the ATLAS particle-flow reconstruction method. The anti-kt jet algorithm with radius parameter R=0.4 is the primary jet definition used for both jet types. This result presents new jet energy scale and resolution measurements in the high pile-up conditions of late LHC Run 2 as well as a full calibration of particle-flow jets in ATLAS. Jets are initially calibrated using a sequence of simulation-based corrections. Next, several in situ techniques are employed to correct for differences between data and simulation and to measure the resolution of jets. The systematic uncertainties in the jet energy scale for central jets (|η|<1.2) vary from 1% for a wide range of high-pT jets (2502.5 TeV). The relative jet energy resolution is measured and ranges from (24±1.5)% at 20 GeV to (6±0.5)% at 300 GeV.
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| 17. |
- Aad, G, et al.
(författare)
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Measurement of b-quark fragmentation properties in jets using the decay B± → J/ψK± in pp collisions at s√ = 13 TeV with the ATLAS detector
- 2021
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Ingår i: Journal of High Energy Physics. - : Springer. - 1029-8479 .- 1126-6708. ; 2021:12
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Tidskriftsartikel (refereegranskat)abstract
- The fragmentation properties of jets containing b-hadrons are studied using charged B mesons in 139 fb−1 of pp collisions at s√ = 13 TeV, recorded with the ATLAS detector at the LHC during the period from 2015 to 2018. The B mesons are reconstructed using the decay of B± into J/ψK±, with the J/ψ decaying into a pair of muons. Jets are reconstructed using the anti-kt algorithm with radius parameter R = 0.4. The measurement determines the longitudinal and transverse momentum profiles of the reconstructed B hadrons with respect to the axes of the jets to which they are geometrically associated. These distributions are measured in intervals of the jet transverse momentum, ranging from 50 GeV to above 100 GeV. The results are corrected for detector effects and compared with several Monte Carlo predictions using different parton shower and hadronisation models. The results for the longitudinal and transverse profiles provide useful inputs to improve the description of heavy-flavour fragmentation in jets.
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| 18. |
- Aad, G, et al.
(författare)
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Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb−1 of Pb+Pb data with the ATLAS detector
- 2021
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Ingår i: Journal of High Energy Physics. - : SPRINGER. - 1029-8479 .- 1126-6708. ; 2021:3
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a measurement of light-by-light scattering based on Pb+Pb collision data recorded by the ATLAS experiment during Run 2 of the LHC. The study uses 2.2 nb−1 of integrated luminosity collected in 2015 and 2018 at sNN = 5.02 TeV. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy ETγ> 2.5 GeV, pseudorapidity |ηγ| < 2.37, diphoton invariant mass mγγ> 5 GeV, and with small diphoton transverse momentum and diphoton acoplanarity. The integrated and differential fiducial cross sections are measured and compared with theoretical predictions. The diphoton invariant mass distribution is used to set limits on the production of axion-like particles. This result provides the most stringent limits to date on axion-like particle production for masses in the range 6–100 GeV. Cross sections above 2 to 70 nb are excluded at the 95% CL in that mass interval. [Figure not available: see fulltext.] © 2021, The Author(s).
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| 19. |
- Aad, G, et al.
(författare)
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Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at √s=13 TeV with the ATLAS detector
- 2021
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:8
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (tt¯ Z) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on s=13 TeV proton–proton collision data with an integrated luminosity of 139 fb - 1, recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be σtt¯Z= 0.99 ± 0.05 (stat.) ±0.08 (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the tt¯ Z system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a χ2/ ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions. © 2021, The Author(s).
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| 20. |
- Aad, G, et al.
(författare)
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Medium-Induced Modification of Z -Tagged Charged Particle Yields in Pb+Pb Collisions at 5.02 TeV with the ATLAS Detector
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 1079-7114 .- 0031-9007. ; 126:7
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Tidskriftsartikel (refereegranskat)abstract
- The yield of charged particles opposite to a Z boson with large transverse momentum (pT) is measured in 260 pb-1 of pp and 1.7 nb-1 of Pb+Pb collision data at 5.02 TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The Z boson tag is used to select hard-scattered partons with specific kinematics, and to observe how their showers are modified as they propagate through the quark-gluon plasma created in Pb+Pb collisions. Compared with pp collisions, charged-particle yields in Pb+Pb collisions show significant modifications as a function of charged-particle pT in a way that depends on event centrality and Z boson pT. The data are compared with a variety of theoretical calculations and provide new information about the medium-induced energy loss of partons in a pT regime difficult to measure through other channels. © 2021 CERN.
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| 21. |
- Aad, G, et al.
(författare)
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Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √s = 13 TeV
- 2021
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 16:7
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS experiment at the Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m2. This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb-1 of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using Z boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC. © 2021 CERN for the benefit of the ATLAS collaboration. Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence
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| 22. |
- Aad, G., et al.
(författare)
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Search for a heavy Higgs boson decaying into a Z boson and another heavy Higgs boson in the ℓℓbb and ℓℓWW final states in pp collisions at √s=13 TeV with the ATLAS detector
- 2021
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6052 .- 1434-6044. ; 81:5
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Tidskriftsartikel (refereegranskat)abstract
- A search for a heavy neutral Higgs boson, A, decaying into a Z boson and another heavy Higgs boson, H, is performed using a data sample corresponding to an integrated luminosity of 139 fb- 1 from proton–proton collisions at s=13 TeV recorded by the ATLAS detector at the LHC. The search considers the Z boson decaying into electrons or muons and the H boson into a pair of b-quarks or W bosons. The mass range considered is 230–800 GeV for the A boson and 130–700 GeV for the H boson. The data are in good agreement with the background predicted by the Standard Model, and therefore 95% confidence-level upper limits for σ×B(A→ZH)×B(H→bborH→WW) are set. The upper limits are in the range 0.0062–0.380 pb for the H→ bb channel and in the range 0.023–8.9 pb for the H→ WW channel. An interpretation of the results in the context of two-Higgs-doublet models is also given.
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| 23. |
- Aad, G, et al.
(författare)
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Search for bottom-squark pair production in pp collision events at s =13 TeV with hadronically decaying τ -leptons, b -jets, and missing transverse momentum using the ATLAS detector
- 2021
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 104:3
-
Tidskriftsartikel (refereegranskat)abstract
- A search for pair production of bottom squarks in events with hadronically decaying τ-leptons, b-tagged jets, and large missing transverse momentum is presented. The analyzed dataset is based on proton-proton collisions at √s=13 TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector from 2015 to 2018, and corresponds to an integrated luminosity of 139 fb−1. The observed data are compatible with the expected Standard Model background. Results are interpreted in a simplified model where each bottom squark is assumed to decay into the second-lightest neutralino ˜χ02 and a bottom quark, with ˜χ02 decaying into a Higgs boson and the lightest neutralino ˜χ01. The search focuses on final states where at least one Higgs boson decays into a pair of hadronically decaying τ-leptons. This allows the acceptance and thus the sensitivity to be significantly improved relative to the previous results at low masses of the ˜χ02, where bottom-squark masses up to 850 GeV are excluded at the 95% confidence level, assuming a mass difference of 130 GeV between ˜χ02 and ˜χ01. Model-independent upper limits are also set on the cross section of processes beyond the Standard Model.
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| 24. |
- Aad, G, et al.
(författare)
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Search for charged Higgs bosons decaying into a top quark and a bottom quark at √s = 13 TeV with the ATLAS detector
- 2021
-
Ingår i: Journal of High Energy Physics. - : Springer Nature. - 1029-8479 .- 1126-6708. ; 2021:6
-
Tidskriftsartikel (refereegranskat)abstract
- A search for charged Higgs bosons decaying into a top quark and a bottom quark is presented. The data analysed correspond to 139 fb−1 of proton-proton collisions at s = 13 TeV, recorded with the ATLAS detector at the LHC. The production of a heavy charged Higgs boson in association with a top quark and a bottom quark, pp → tbH+ → tbtb, is explored in the H+ mass range from 200 to 2000 GeV using final states with jets and one electron or muon. Events are categorised according to the multiplicity of jets and b-tagged jets, and multivariate analysis techniques are used to discriminate between signal and background events. No significant excess above the background-only hypothesis is observed and exclusion limits are derived for the production cross-section times branching ratio of a charged Higgs boson as a function of its mass; they range from 3.6 pb at 200 GeV to 0.036 pb at 2000 GeV at 95% confidence level. The results are interpreted in the hMSSM and Mh125 scenarios.
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| 25. |
- Aad, G, et al.
(författare)
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Search for dark matter in events with missing transverse momentum and a Higgs boson decaying into two photons in pp collisions at √s = 13 TeV with the ATLAS detector
- 2021
-
Ingår i: Journal of High Energy Physics. - : Springer. - 1029-8479 .- 1126-6708. ; 2021:10
-
Tidskriftsartikel (refereegranskat)abstract
- A search for dark-matter particles in events with large missing transverse momentum and a Higgs boson candidate decaying into two photons is reported. The search uses 139 fb−1 of proton-proton collision data collected at s = 13 TeV with the ATLAS detector at the CERN LHC between 2015 and 2018. No significant excess of events over the Standard Model predictions is observed. The results are interpreted by extracting limits on three simplified models that include either vector or pseudoscalar mediators and predict a final state with a pair of dark-matter candidates and a Higgs boson decaying into two photons.
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| 26. |
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| 27. |
- Aad, G, et al.
(författare)
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Search for dark matter produced in association with a single top quark in √s=13 TeV pp collisions with the ATLAS detector
- 2021
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:10
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at s=13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb - 1. No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered. © 2021, The Author(s).
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| 28. |
- Aad, G., et al.
(författare)
-
Search for long-lived charginos based on a disappearing-track signature using 136 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector
- 2022
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 82:7
-
Tidskriftsartikel (refereegranskat)abstract
- A search for long-lived charginos produced either directly or in the cascade decay of heavy prompt gluino states is presented. The search is based on proton–proton collision data collected at a centre-of-mass energy of s√s = 13 TeVeV between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 136 fb−1. Long-lived charginos are characterised by a distinct signature of a short and then disappearing track, and are reconstructed using at least four measurements in the ATLAS pixel detector, with no subsequent measurements in the silicon-microstrip tracking volume nor any associated energy deposits in the calorimeter. The final state is complemented by a large missing transverse-momentum requirement for triggering purposes and at least one high-transverse-momentum jet. No excess above the expected backgrounds is observed. Exclusion limits are set at 95% confidence level on the masses of the chargino and gluino for different chargino lifetimes. Chargino masses up to 660 (210) GeVeV are excluded in scenarios where the chargino is a pure wino (higgsino). For charginos produced during the cascade decay of a heavy gluino, gluinos with masses below 2.1 TeVeV are excluded for a chargino mass of 300 GeVeV and a lifetime of 0.2 ns.
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| 29. |
- Aad, G, et al.
(författare)
-
Search for new phenomena in events with an energetic jet and missing transverse momentum in pp collisions at s =13 TeV with the ATLAS detector
- 2021
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 103:11
-
Tidskriftsartikel (refereegranskat)abstract
- Results of a search for new physics in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 139 fb-1 at a center-of-mass energy of 13 TeV collected in the period 2015-2018 with the ATLAS detector at the Large Hadron Collider. Compared to previous publications, in addition to an increase of almost a factor of four in the data size, the analysis implements a number of improvements in the signal selection and the background determination leading to enhanced sensitivity. Events are required to have at least one jet with transverse momentum above 150 GeV and no reconstructed leptons (e, μ or τ) or photons. Several signal regions are considered with increasing requirements on the missing transverse momentum starting at 200 GeV. Overall agreement is observed between the number of events in data and the Standard Model predictions. Model-independent 95% confidence-level limits on visible cross sections for new processes are obtained in the range between 736 fb and 0.3 fb. Results are also translated into improved exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, supersymmetric particles in several compressed scenarios, axionlike particles, and new scalar particles in dark-energy-inspired models. In addition, the data are translated into bounds on the invisible branching ratio of the Higgs boson. © 2021 CERN.
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| 30. |
- Aad, G, et al.
(författare)
-
Search for new phenomena in final states with b-jets and missing transverse momentum in √s = 13 TeV pp collisions with the ATLAS detector
- 2021
-
Ingår i: Journal of High Energy Physics. - : Springer. - 1029-8479 .- 1126-6708.
-
Tidskriftsartikel (refereegranskat)abstract
- The results of a search for new phenomena in final states with b-jets and missing transverse momentum using 139 fb−1 of proton-proton data collected at a centre-of-mass energy s = 13 TeV by the ATLAS detector at the LHC are reported. The analysis targets final states produced by the decay of a pair-produced supersymmetric bottom squark into a bottom quark and a stable neutralino. The analysis also seeks evidence for models of pair production of dark matter particles produced through the decay of a generic scalar or pseudoscalar mediator state in association with a pair of bottom quarks, and models of pair production of scalar third-generation down-type leptoquarks. No significant excess of events over the Standard Model background expectation is observed in any of the signal regions considered by the analysis. Bottom squark masses below 1270 GeV are excluded at 95% confidence level if the neutralino is massless. In the case of nearly mass-degenerate bottom squarks and neutralinos, the use of dedicated secondary-vertex identification techniques permits the exclusion of bottom squarks with masses up to 660 GeV for mass splittings between the squark and the neutralino of 10 GeV. These limits extend substantially beyond the regions of parameter space excluded by similar ATLAS searches performed previously. [Figure not available: see fulltext.] © 2021, The Author(s).
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| 31. |
- Aad, G, et al.
(författare)
-
Search for pair production of scalar leptoquarks decaying into first- or second-generation leptons and top quarks in proton–proton collisions at √s = 13 TeV with the ATLAS detector
- 2021
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:4
-
Tidskriftsartikel (refereegranskat)abstract
- A search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented. This is the first leptoquark search using ATLAS data to investigate top-philic cross-generational couplings that could provide explanations for recently observed anomalies in B meson decays. This analysis targets high leptoquark masses which cause the decay products of each resultant top quark to be contained within a single high-pT large-radius jet. The full Run 2 dataset is exploited, consisting of 139fb-1 of data collected from proton–proton collisions at s=13TeV from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. In the absence of any significant deviation from the background expectation, lower limits on the leptoquark masses are set at 1480GeV and 1470GeV for the electron and muon channel, respectively. © 2021, The Author(s).
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| 32. |
- Aad, G, et al.
(författare)
-
Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s=13 with the ATLAS detector
- 2021
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:7
-
Tidskriftsartikel (refereegranskat)abstract
- The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two W bosons, the lightest neutralinos (χ~10), and quarks, are presented: the signal is characterised by the presence of a single charged lepton (e± or μ±) from a W boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb- 1 of proton–proton collision data taken at a centre-of-mass energy s=13 delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2 (1.4) are excluded at 95% confidence level for a light χ~10.
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| 33. |
- Aad, G, et al.
(författare)
-
Search for supersymmetry in events with four or more charged leptons in 139 fb−1 of √s = 13 TeV pp collisions with the ATLAS detector
- 2021
-
Ingår i: Journal of High Energy Physics. - : SPRINGER. - 1029-8479 .- 1126-6708. ; 2021:7
-
Tidskriftsartikel (refereegranskat)abstract
- A search for supersymmetry in events with four or more charged leptons (electrons, muons and τ-leptons) is presented. The analysis uses a data sample corresponding to 139 fb−1 of proton-proton collisions delivered by the Large Hadron Collider at s = 13 TeV and recorded by the ATLAS detector. Four-lepton signal regions with up to two hadronically decaying τ-leptons are designed to target several supersymmetric models, while a general five-lepton signal region targets any new physics phenomena leading to a final state with five charged leptons. Data yields are consistent with Standard Model expectations and results are used to set upper limits on contributions from processes beyond the Standard Model. Exclusion limits are set at the 95% confidence level in simplified models of general gauge-mediated supersymmetry, excluding higgsino masses up to 540 GeV. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to charged leptons, lower limits of 1.6 TeV, 1.2 TeV, and 2.5 TeV are placed on wino, slepton and gluino masses, respectively. [Figure not available: see fulltext.] © 2021, The Author(s).
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| 34. |
- Aad, G, et al.
(författare)
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Search for trilepton resonances from chargino and neutralino pair production in s =13 TeV pp collisions with the ATLAS detector
- 2021
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 103:11
-
Tidskriftsartikel (refereegranskat)abstract
- A search is performed for the electroweak pair production of charginos and associated production of a chargino and neutralino, each of which decays through an R-parity-violating coupling into a lepton and a W, Z, or Higgs boson. The trilepton invariant-mass spectrum is constructed from events with three or more leptons, targeting chargino decays that include an electron or muon and a leptonically decaying Z boson. The analyzed dataset corresponds to an integrated luminosity of 139 fb-1 of proton-proton collision data produced by the Large Hadron Collider at a center-of-mass energy of s=13 TeV and collected by the ATLAS experiment between 2015 and 2018. The data are found to be consistent with predictions from the Standard Model. The results are interpreted as limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model. Limits are also set on the production of charginos and neutralinos for a minimal supersymmetric Standard Model with an approximate B-L symmetry. Charginos and neutralinos with masses between 100 and 1100 GeV are excluded depending on the assumed decay branching fractions into a lepton (electron, muon, or τ lepton) plus a boson (W, Z, or Higgs). © 2021 CERN.
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| 35. |
- Aad, G, et al.
(författare)
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Test of the universality of τ and μ lepton couplings in W-boson decays with the ATLAS detector
- 2021
-
Ingår i: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2473 .- 1745-2481. ; 17:7, s. 813-818
-
Tidskriftsartikel (refereegranskat)abstract
- The standard model of particle physics encapsulates our best current understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the decay rate of W bosons to τ leptons and muons, R(τ/μ), constitutes an important test of this axiom. Using 139 fb−1 of proton–proton collisions recorded with the ATLAS detector at a centre-of-mass energy of 13 TeV, we report a measurement of this quantity from di-leptonic tt¯ events where the top quarks decay into a W boson and a bottom quark. We can distinguish muons originating from W bosons and those originating from an intermediate τ lepton through the muon transverse impact parameter and differences in the muon transverse momentum spectra. The measured value of R(τ/μ) is 0.992 ± 0.013 [± 0.007(stat) ± 0.011(syst)] and is in agreement with the hypothesis of universal lepton couplings as postulated in the standard model. This is the only such measurement from the Large Hadron Collider, so far, and obtains twice the precision of previous measurements.
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| 36. |
- Akerlund, Cecilia A., I, et al.
(författare)
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Clinical descriptors of disease trajectories in patients with traumatic brain injury in the intensive care unit (CENTER-TBI) : a multicentre observational cohort study
- 2024
-
Ingår i: Lancet Neurology. - : Elsevier BV. - 1474-4422 .- 1474-4465. ; 23:1, s. 71-80
-
Tidskriftsartikel (refereegranskat)abstract
- Background Patients with traumatic brain injury are a heterogeneous population, and the most severely injured individuals are often treated in an intensive care unit (ICU). The primary injury at impact, and the harmful secondary events that can occur during the first week of the ICU stay, will affect outcome in this vulnerable group of patients. We aimed to identify clinical variables that might distinguish disease trajectories among patients with traumatic brain injury admitted to the ICU. Methods We used data from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) prospective observational cohort study. We included patients aged 18 years or older with traumatic brain injury who were admitted to the ICU at one of the 65 CENTER-TBI participating centres, which range from large academic hospitals to small rural hospitals. For every patient, we obtained pre-injury data and injury features, clinical characteristics on admission, demographics, physiological parameters, laboratory features, brain biomarkers (ubiquitin carboxy-terminal hydrolase L1 [UCH-L1], S100 calcium-binding protein B [S100B], tau, neurofilament light [NFL], glial fibrillary acidic protein [GFAP], and neuron-specific enolase [NSE]), and information about intracranial pressure lowering treatments during the first 7 days of ICU stay. To identify clinical variables that might distinguish disease trajectories, we applied a novel clustering method to these data, which was based on a mixture of probabilistic graph models with a Markov chain extension. The relation of clusters to the extended Glasgow Outcome Scale (GOS-E) was investigated. Findings Between Dec 19, 2014, and Dec 17, 2017, 4509 patients with traumatic brain injury were recruited into the CENTER-TBI core dataset, of whom 1728 were eligible for this analysis. Glucose variation (defined as the difference between daily maximum and minimum glucose concentrations) and brain biomarkers (S100B, NSE, NFL, tau, UCH-L1, and GFAP) were consistently found to be the main clinical descriptors of disease trajectories (ie, the leading variables contributing to the distinguishing clusters) in patients with traumatic brain injury in the ICU. The disease trajectory cluster to which a patient was assigned in a model was analysed as a predictor together with variables from the IMPACT model, and prediction of both mortality and unfavourable outcome (dichotomised GOS-E <= 4) was improved. Interpretation First-day ICU admission data are not the only clinical descriptors of disease trajectories in patients with traumatic brain injury. By analysing temporal variables in our study, variation of glucose was identified as the most important clinical descriptor that might distinguish disease trajectories in the ICU, which should direct further research. Biomarkers of brain injury (S100B, NSE, NFL, tau, UCH-L1, and GFAP) were also top clinical descriptors over time, suggesting they might be important in future clinical practice.
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| 37. |
- Almora, Osbel, et al.
(författare)
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Device Performance of Emerging Photovoltaic Materials (Version 1)
- 2020
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 11:11
-
Tidskriftsartikel (refereegranskat)abstract
- Emerging photovoltaics (PVs) focus on a variety of applications complementing large scale electricity generation. Organic, dye-sensitized, and some perovskite solar cells are considered in building integration, greenhouses, wearable, and indoor applications, thereby motivating research on flexible, transparent, semitransparent, and multi-junction PVs. Nevertheless, it can be very time consuming to find or develop an up-to-date overview of the state-of-the-art performance for these systems and applications. Two important resources for recording research cells efficiencies are the National Renewable Energy Laboratory chart and the efficiency tables compiled biannually by Martin Green and colleagues. Both publications provide an effective coverage over the established technologies, bridging research and industry. An alternative approach is proposed here summarizing the best reports in the diverse research subjects for emerging PVs. Best performance parameters are provided as a function of the photovoltaic bandgap energy for each technology and application, and are put into perspective using, e.g., the Shockley–Queisser limit. In all cases, the reported data correspond to published and/or properly described certified results, with enough details provided for prospective data reproduction. Additionally, the stability test energy yield is included as an analysis parameter among state-of-the-art emerging PVs.
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| 38. |
- Andrean, Stefio Y., et al.
(författare)
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A search for the decays of stopped long-lived particles at root s=13 TeV with the ATLAS detector
- 2021
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :7
-
Tidskriftsartikel (refereegranskat)abstract
- A search for long-lived particles, which have come to rest within the ATLAS detector, is presented. The subsequent decays of these particles can produce high-momentum jets, resulting in large out-of-time energy deposits in the ATLAS calorimeters. These decays are detected using data collected during periods in the LHC bunch structure when collisions are absent. The analysed dataset is composed of events from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy of root s = 13TeV and recorded by the ATLAS experiment during 2017 and 2018. The dataset used for this search corresponds to a total live time of 579 hours. The results of this search are used to derive lower limits on the mass of gluino R-hadrons, assuming a branching fraction B((g) over tilde -> q (q) over bar(chi) over tilde (0)(1)) = 100%, with masses of up to 1.4TeV excluded for gluino lifetimes of 10(-5) to 10(3) s.
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| 39. |
- Andrean, Stefio Y., et al.
(författare)
-
Configuration and performance of the ATLAS b-jet triggers in Run 2
- 2021
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:12
-
Tidskriftsartikel (refereegranskat)abstract
- Several improvements to the ATLAS triggers used to identify jets containing b-hadrons (b-jets) were implemented for data-taking during Run 2 of the Large Hadron Collider from 2016 to 2018. These changes include reconfiguring the b-jet trigger software to improve primary-vertex finding and allow more stable running in conditions with high pile-up, and the implementation of the functionality needed to run sophisticated taggers used by the offline reconstruction in an online environment. These improvements yielded an order of magnitude better light-flavour jet rejection for the same b-jet identification efficiency compared to the performance in Run 1 (2011-2012). The efficiency to identify b-jets in the trigger, and the conditional efficiency for b-jets that satisfy offline b-tagging requirements to pass the trigger are also measured. Correction factors are derived to calibrate the b-tagging efficiency in simulation to match that observed in data. The associated systematic uncertainties are substantially smaller than in previous measurements. In addition, b-jet triggers were operated for the first time during heavy-ion data-taking, using dedicated triggers that were developed to identify semileptonic b-hadron decays by selecting events with geometrically overlapping muons and jets.
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| 40. |
- Andrean, Stefio Y., et al.
(författare)
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Determination of the parton distribution functions of the proton from ATLAS measurements of differential W-+/- and Z boson production in association with jets
- 2021
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :7
-
Tidskriftsartikel (refereegranskat)abstract
- This article presents a new set of proton parton distribution functions, AT-LASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of W+ and W- boson and Z boson production in association with jets in pp collisions at root s = 8TeV performed by the ATLAS experiment at the LHC with integrated luminosities of 20.2 fb(-1) and 19.9 fb(-1), respectively. The analysis also considers the ATLAS measurements of differential W-+/- and Z boson production at root s = 7 TeV with an integrated luminosity of 4.6 fb(-1) and deep-inelastic-scattering data from e(+/-) p collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken x is shown, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x less than or similar to 0.02 found by previous ATLAS analyses.
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| 41. |
- Andrean, Stefio Y., et al.
(författare)
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Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at root s=13 TeV with the ATLAS detector
- 2021
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 819
-
Tidskriftsartikel (refereegranskat)abstract
- A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass m(ll) < 30 GeV is presented. The analysis is performed using 139 fb(-1) of proton-proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H -> ll(gamma) process is found with a significance of 3.2 over the background-only hypothesis, compared to an expected significance of 2.1 for the Standard Model prediction. The best-fit value of the signal-strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is mu = 1.5 +/- 0.5. The Higgs boson production cross-section times the H -> ll(gamma) branching ratio for m(ll) < 30 GeV is determined to be 8.7(-2.7)(+2.8) fb.
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| 42. |
- Andrean, Stefio Y., et al.
(författare)
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Measurement of the production cross section of pairs of isolated photons in pp collisions at 13 TeV with the ATLAS detector
- 2021
-
Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :11
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of prompt photon-pair production in proton-proton collisions at s√s = 13 TeV is presented. The data were recorded by the ATLAS detector at the LHC with an integrated luminosity of 139 fb−1. Events with two photons in the well-instrumented region of the detector are selected. The photons are required to be isolated and have a transverse momentum of pT,γ1(2)pT,γ1(2) > 40 (30) GeV for the leading (sub-leading) photon. The differential cross sections as functions of several observables for the diphoton system are measured and compared with theoretical predictions from state-of-the-art Monte Carlo and fixed-order calculations. The QCD predictions from next-to-next-to-leading-order calculations and multi-leg merged calculations are able to describe the measured integrated and differential cross sections within uncertainties, whereas lower-order calculations show significant deviations, demonstrating that higher-order perturbative QCD corrections are crucial for this process. The resummed predictions with parton showers additionally provide an excellent description of the low transverse-momentum regime of the diphoton system.
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| 43. |
- Andrean, Stefio Y., et al.
(författare)
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Measurements of differential cross-sections in four-lepton events in 13 TeV proton-proton collisions with the ATLAS detector
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of four-lepton differential and integrated fiducial cross-sections in events with two same-flavour, opposite-charge electron or muon pairs are presented. The data correspond to 139 fb(-1) of root s = 13 TeV proton-proton collisions, collected by the ATLAS detector during Run 2 of the Large Hadron Collider (2015-2018). The final state has contributions from a number of interesting Standard Model processes that dominate in different four-lepton invariant mass regions, including single Z boson production, Higgs boson production and on-shell ZZ production, with a complex mix of interference terms, and possible contributions from physics beyond the Standard Model. The differential cross-sections include the four-lepton invariant mass inclusively, in slices of other kinematic variables, and in different lepton flavour categories. Also measured are dilepton invariant masses, transverse momenta, and angular correlation variables, in four regions of four-lepton invariant mass, each dominated by different processes. The measurements are corrected for detector effects and are compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. The Z -> 4l branching fraction is extracted, giving a value of (4.41 +/- 0.30) x 10(-6). Constraints on effective field theory parameters and a model based on a spontaneously broken B - L gauge symmetry are also evaluated. Further reinterpretations can be performed with the provided information.
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| 44. |
- Andrean, Stefio Y., et al.
(författare)
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Measurements of sensor radiation damage in the ATLAS inner detector using leakage currents
- 2021
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Ingår i: Journal of Instrumentation. - : IOP Publishing Ltd. - 1748-0221. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- Non-ionizing energy loss causes bulk damage to the silicon sensors of the ATLAS pixel and strip detectors. This damage has important implications for data-taking operations, charged-particle track reconstruction, detector simulations, and physics analysis. This paper presents simulations and measurements of the leakage current in the ATLAS pixel detector and semiconductor tracker as a function of location in the detector and time, using data collected in Run 1 (2010–2012) and Run 2 (2015–2018) of the Large Hadron Collider. The extracted fluence shows a much stronger |z|-dependence in the innermost layers than is seen in simulation. Furthermore, the overall fluence on the second innermost layer is significantly higher than in simulation, with better agreement in layers at higher radii. These measurements are important for validating the simulation models and can be used in part to justify safety factors for future detector designs and interventions.
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| 45. |
- Andrean, Stefio Y., et al.
(författare)
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Observation and Measurement of Forward Proton Scattering in Association with Lepton Pairs Produced via the Photon Fusion Mechanism at ATLAS
- 2020
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 125:26
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Tidskriftsartikel (refereegranskat)abstract
- The observation of forward proton scattering in association with lepton pairs (e(+)e(-) + p or mu(+)mu(-) + p) produced via photon fusion is presented. The scattered proton is detected by the ATLAS Forward Proton spectrometer, while the leptons are reconstructed by the central ATLAS detector. Proton-proton collision data recorded in 2017 at a center-of-mass energy of root s = 13 TeV are analyzed, corresponding to an integrated luminosity of 14.6 fb(-1). A total of 57 (123) candidates in the ee + p (mu mu + p) final state arc selected, allowing the background-only hypothesis to be rejected with a significance exceeding 5 standard deviations in each channel. Proton-tagging techniques are introduced for cross-section measurements in the fiducial detector acceptance, corresponding to sigma(ee)(+p) = 11.0 +/- 2.6(stat) 1.2(syst) +/- 0.3(lumi) and sigma(mu)(mu+)(p) = 7.2 +/- 1.6(stat) +/- 0.9(syst) 0.2(lumi) fb in the dielectron and dimuon channel, respectively.
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| 46. |
- Andrean, Stefio Y., et al.
(författare)
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Performance of the ATLAS Level-1 topological trigger in Run 2
- 2022
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 82:1
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Tidskriftsartikel (refereegranskat)abstract
- During LHC Run 2 (2015-2018) the ATLAS Level-1 topological trigger allowed efficient data-taking by the ATLAS experiment at luminosities up to 2.1 x10(34) cm(-2) s(-1), which exceeds the design value by a factor of two. The system was installed in 2016 and operated in 2017 and 2018. It uses Field Programmable Gate Array processors to select interesting events by placing kinematic and angular requirements on electromagnetic clusters, jets, tau-leptons, muons and the missing transverse energy. It allowed to significantly improve the background event rejection and signal event acceptance, in particular for Higgs and B-physics processes.
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| 47. |
- Andrean, Stefio Y., 1991-, et al.
(författare)
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Search for chargino–neutralino pair production in final states with three leptons and missing transverse momentum in √s=13 TeV pp collisions with the ATLAS detector
- 2021
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:12
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Tidskriftsartikel (refereegranskat)abstract
- A search for chargino–neutralino pair productionin three-lepton final states with missing transverse momentum is presented. The study is based on a dataset of √s =13 TeV pp collisions recorded with the ATLAS detectorat the LHC, corresponding to an integrated luminosity of 139 fb−1. No significant excess relative to the Standard Model predictions is found in data. The results are interpreted in simplified models of supersymmetry, and statistically combined with results from a previous ATLAS search for compressed spectra in two-lepton final states. Various scenarios for the production and decay of charginos (χ˜ ±1 ) and neutralinos (χ˜ 02 ) are considered. For pure higgsino χ˜ ±1 χ˜ 02 pair production scenarios, exclusion limits at 95% confidence level are set on χ˜ 02 masses up to 210 GeV. Limits are also set for pure wino χ˜ ±1 χ˜ 02 pair production, on χ˜ 02 masses up to 640 GeV for decays via on-shell W and Z bosons, up to 300 GeV for decays via off-shell W and Z bosons, and up to 190 GeV for decays via W and Standard Model Higgs bosons.
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| 48. |
- Andrean, Stefio Y., et al.
(författare)
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Search for dark matter produced in association with a Standard Model Higgs boson decaying into b-quarks using the full Run 2 dataset from the ATLAS detector
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The production of dark matter in association with Higgs bosons is predicted in several extensions of the Standard Model. An exploration of such scenarios is presented, considering final states with missing transverse momentum and b-tagged jets consistent with a Higgs boson. The analysis uses proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by the ATLAS experiment at the LHC during Run 2, amounting to an integrated luminosity of 139 fb−1. The analysis, when compared with previous searches, benefits from a larger dataset, but also has further improvements providing sensitivity to a wider spectrum of signal scenarios. These improvements include both an optimised event selection and advances in the object identification, such as the use of the likelihood-based significance of the missing transverse momentum and variable-radius track-jets. No significant deviation from Standard Model expectations is observed. Limits are set, at 95% confidence level, in two benchmark models with two Higgs doublets extended by either a heavy vector boson Z′ or a pseudoscalar singlet a and which both provide a dark matter candidate χ. In the case of the two-Higgs-doublet model with an additional vector boson Z′, the observed limits extend up to a Z′ mass of 3 TeV for a mass of 100 GeV for the dark matter candidate. The two-Higgs-doublet model with a dark matter particle mass of 10 GeV and an additional pseudoscalar a is excluded for masses of the a up to 520 GeV and 240 GeV for tan β = 1 and tan β = 10 respectively. Limits on the visible cross-sections are set and range from to 0.05 fb to 3.26 fb, depending on the missing transverse momentum and b-quark jet multiplicity requirements.
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| 49. |
- Andrean, Stefio Y., et al.
(författare)
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Search for Displaced Leptons in root s=13 TeV pp Collisions with the ATLAS Detector
- 2021
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 127:5
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Tidskriftsartikel (refereegranskat)abstract
- A search for charged leptons with large impact parameters using 139 fb(-1) of root s = 13 TeV pp collision data from the ATLAS detector at the LHC is presented, addressing a long-standing gap in coverage of possible new physics signatures. Results are consistent with the background prediction. This search provides unique sensitivity to long-lived scalar supersymmetric lepton partners (sleptons). For lifetimes of 0.1 ns, selectron, smuon, and stau masses up to 720, 680, and 340 GeV, respectively, are excluded at 95% confidence level, drastically improving on the previous best limits from LEP.
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| 50. |
- Andrean, Stefio Y., et al.
(författare)
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Search for exotic decays of the Higgs boson into long-lived particles in pp collisions at √s=13 TeV using displaced vertices in the ATLAS inner detector
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- A novel search for exotic decays of the Higgs boson into pairs of long-lived neutral particles, each decaying into a bottom quark pair, is performed using 139 fb−1 of √s = 13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Events consistent with the production of a Higgs boson in association with a leptonically decaying Z boson are analysed. Long-lived particle (LLP) decays are reconstructed from inner-detector tracks as displaced vertices with high mass and track multiplicity relative to Standard Model processes. The analysis selection requires the presence of at least two displaced vertices, effectively suppressing Standard Model backgrounds. The residual background contribution is estimated using a data-driven technique. No excess over Standard Model predictions is observed, and upper limits are set on the branching ratio of the Higgs boson to LLPs. Branching ratios above 10% are excluded at 95% confidence level for LLP mean proper lifetimes cτ as small as 4 mm and as large as 100 mm. For LLP masses below 40 GeV, these results represent the most stringent constraint in this lifetime regime.
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