SwePub - sökning: WFRF:(Ask Maria)

Numrering	Referens	Omslagsbild	Hitta
1.	Lundgren, Markus, et al. (författare) Analgesic antipyretic use among young children in the TEDDY study : No association with islet autoimmunity 2017 Ingår i: BMC Pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 17:1 Tidskriftsartikel (refereegranskat)abstract Background: The use of analgesic antipyretics (ANAP) in children have long been a matter of controversy. Data on their practical use on an individual level has, however, been scarce. There are indications of possible effects on glucose homeostasis and immune function related to the use of ANAP. The aim of this study was to analyze patterns of analgesic antipyretic use across the clinical centers of The Environmental Determinants of Diabetes in the Young (TEDDY) prospective cohort study and test if ANAP use was a risk factor for islet autoimmunity. Methods: Data were collected for 8542 children in the first 2.5 years of life. Incidence was analyzed using logistic regression with country and first child status as independent variables. Holm's procedure was used to adjust for multiplicity of intercountry comparisons. Time to autoantibody seroconversion was analyzed using a Cox proportional hazards model with cumulative analgesic use as primary time dependent covariate of interest. For each categorization, a generalized estimating equation (GEE) approach was used. Results: Higher prevalence of ANAP use was found in the U.S. (95.7%) and Sweden (94.8%) compared to Finland (78.1%) and Germany (80.2%). First-born children were more commonly given acetaminophen (OR 1.26; 95% CI 1.07, 1.49; p = 0.007) but less commonly Non-Steroidal Anti-inflammatory Drugs (NSAID) (OR 0.86; 95% CI 0.78, 0.95; p = 0.002). Acetaminophen and NSAID use in the absence of fever and infection was more prevalent in the U.S. (40.4%; 26.3% of doses) compared to Sweden, Finland and Germany (p < 0.001). Acetaminophen or NSAID use before age 2.5 years did not predict development of islet autoimmunity by age 6 years (HR 1.02, 95% CI 0.99-1.09; p = 0.27). In a sub-analysis, acetaminophen use in children with fever weakly predicted development of islet autoimmunity by age 3 years (HR 1.05; 95% CI 1.01-1.09; p = 0.024). Conclusions: ANAP use in young children is not a risk factor for seroconversion by age 6 years. Use of ANAP is widespread in young children, and significantly higher in the U.S. compared to other study sites, where use is common also in absence of fever and infection.
2.	Haghighi, Mona, et al. (författare) A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study 2016 Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6 Tidskriftsartikel (refereegranskat)abstract Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
3.	Johnson, Randi K., et al. (författare) Metabolite-related dietary patterns and the development of islet autoimmunity 2019 Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1 Tidskriftsartikel (refereegranskat)abstract The role of diet in type 1 diabetes development is poorly understood. Metabolites, which reflect dietary response, may help elucidate this role. We explored metabolomics and lipidomics differences between 352 cases of islet autoimmunity (IA) and controls in the TEDDY (The Environmental Determinants of Diabetes in the Young) study. We created dietary patterns reflecting pre-IA metabolite differences between groups and examined their association with IA. Secondary outcomes included IA cases positive for multiple autoantibodies (mAb+). The association of 853 plasma metabolites with outcomes was tested at seroconversion to IA, just prior to seroconversion, and during infancy. Key compounds in enriched metabolite sets were used to create dietary patterns reflecting metabolite composition, which were then tested for association with outcomes in the nested case-control subset and the full TEDDY cohort. Unsaturated phosphatidylcholines, sphingomyelins, phosphatidylethanolamines, glucosylceramides, and phospholipid ethers in infancy were inversely associated with mAb+ risk, while dicarboxylic acids were associated with an increased risk. An infancy dietary pattern representing higher levels of unsaturated phosphatidylcholines and phospholipid ethers, and lower sphingomyelins was protective for mAb+ in the nested case-control study only. Characterization of this high-risk infant metabolomics profile may help shape the future of early diagnosis or prevention efforts. © 2019, The Author(s).
4.	Krischer, Jeffrey P, et al. (författare) Predicting Islet Cell Autoimmunity and Type 1 Diabetes : An 8-Year TEDDY Study Progress Report 2019 Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 42:6, s. 1051-1060 Tidskriftsartikel (refereegranskat)abstract OBJECTIVE: Assessment of the predictive power of The Environmental Determinants of Diabetes in the Young (TEDDY)-identified risk factors for islet autoimmunity (IA), the type of autoantibody appearing first, and type 1 diabetes (T1D).RESEARCH DESIGN AND METHODS: A total of 7,777 children were followed from birth to a median of 9.1 years of age for the development of islet autoantibodies and progression to T1D. Time-dependent sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated to provide estimates of their individual and collective ability to predict IA and T1D.RESULTS: HLA genotype (DR3/4 vs. others) was the best predictor for IA (Youden's index J = 0.117) and single nucleotide polymorphism rs2476601, in PTPN22, was the best predictor for insulin autoantibodies (IAA) appearing first (IAA-first) (J = 0.123). For GAD autoantibodies (GADA)-first, weight at 1 year was the best predictor (J = 0.114). In a multivariate model, the area under the ROC curve (AUC) was 0.678 (95% CI 0.655, 0.701), 0.707 (95% CI 0.676, 0.739), and 0.686 (95% CI 0.651, 0.722) for IA, IAA-first, and GADA-first, respectively, at 6 years. The AUC of the prediction model for T1D at 3 years after the appearance of multiple autoantibodies reached 0.706 (95% CI 0.649, 0.762).CONCLUSIONS: Prediction modeling statistics are valuable tools, when applied in a time-until-event setting, to evaluate the ability of risk factors to discriminate between those who will and those who will not get disease. Although significantly associated with IA and T1D, the TEDDY risk factors individually contribute little to prediction. However, in combination, these factors increased IA and T1D prediction substantially.
5.	Rewers, Marian, et al. (författare) The Environmental Determinants of Diabetes in the Young (TEDDY) Study 2008 Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1150, s. 1-13 Tidskriftsartikel (refereegranskat)abstract The etiology of type 1 diabetes (T1D) remains unknown, but a growing body of evidence points to infectious agents and/or components of early childhood diet. The National Institutes of Health has established the TEDDY Study consortium of six clinical centers in the United States and Europe and a data coordinating center to identify environmental factors predisposing to, or protective against, islet autoimmunity and T1D. From 2004-2009, TEDDY will screen more than 360,000 newborns from both the general population and families already affected by T1D to identify an estimated 17,804 children with high-risk HLA-DR,DQ genotypes. Of those, 7,801 (788 first-degree relatives and 7,013 newborns with no family history of T1D) will be enrolled in prospective follow-up beginning before the age of 4.5 months. As of May 2008, TEDDY has screened more than 250,000 newborns and enrolled nearly 5,000 infants--approximately 70% of the final cohort. Participants are seen every 3 months up to 4 years of age, with subsequent visits every 6 months until the subject is 15 years of age. Blood samples are collected at each visit for detection of candidate infectious agents and nutritional biomarkers; monthly stool samples are collected for infectious agents. These samples are saved in a central repository. Primary endpoints include (1) appearance of one or more islet autoantibodies (to insulin, GAD65 or IA-2) confirmed at two consecutive visits; (2) development of T1D. By age 15, an estimated 800 children will develop islet autoimmunity and 400 will progress to T1D; 67 and 27 children have already reached these endpoints.
6.	Smith, Laura B., et al. (författare) Psychological manifestations of celiac disease autoimmunity in young children 2017 Ingår i: Pediatrics. - : American Academy of Pediatrics (AAP). - 0031-4005 .- 1098-4275. ; 139:3 Tidskriftsartikel (refereegranskat)abstract BACKGROUND AND OBJECTIVES: Psychological symptoms can be associated with celiac disease; abstract however, this association has not been studied prospectively in a pediatric cohort. We examined mother report of psychological functioning in children persistently positive for tissue transglutaminase autoantibodies (tTGA), defined as celiac disease autoimmunity (CDA), compared with children without CDA in a screening population of genetically at-risk children. We also investigated differences in psychological symptoms based on mothers' awareness of their child's CDA status. METHODS: The Environmental Determinants of Diabetes in the Young study followed 8676 children to identify triggers of type 1 diabetes and celiac disease. Children were tested for tTGA beginning at 2 years of age. The Achenbach Child Behavior Checklist assessed child psychological functioning at 3.5 and 4.5 years of age. RESULTS: At 3.5 years, 66 mothers unaware their child had CDA reported more child anxiety and depression, aggressive behavior, and sleep problems than 3651 mothers of children without CDA (all Ps ≤ .03). Unaware-CDA mothers also reported more child anxiety and depression, withdrawn behavior, aggressive behavior, and sleep problems than 440 mothers aware of their child's CDA status (all Ps ≤.04). At 4.5 years, there were no differences. CONCLUSIONS: In 3.5-year-old children, CDA is associated with increased reports of child depression and anxiety, aggressive behavior, and sleep problems when mothers are unaware of their child's CDA status. Mothers' knowledge of their child's CDA status is associated with fewer reports of psychological symptoms, suggesting that awareness of the child's tTGA test results affects reporting of symptoms.
7.	Törn, Carina, et al. (författare) Complement gene variants in relation to autoantibodies to beta cell specific antigens and type 1 diabetes in the TEDDY Study 2016 Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6 Tidskriftsartikel (refereegranskat)abstract A total of 15 SNPs within complement genes and present on the ImmunoChip were analyzed in The Environmental Determinants of Diabetes in the Young (TEDDY) study. A total of 5474 subjects were followed from three months of age until islet autoimmunity (IA: n = 413) and the subsequent onset of type 1 diabetes (n = 115) for a median of 73 months (IQR 54-91). Three SNPs within ITGAM were nominally associated (p < 0.05) with IA: rs1143678 [Hazard ratio; HR 0.80; 95% CI 0.66-0.98; p = 0.032], rs1143683 [HR 0.80; 95% CI 0.65-0.98; p = 0.030] and rs4597342 [HR 1.16; 95% CI 1.01-1.32; p = 0.041]. When type 1 diabetes was the outcome, in DR3/4 subjects, there was nominal significance for two SNPs: rs17615 in CD21 [HR 1.52; 95% CI 1.05-2.20; p = 0.025] and rs4844573 in C4BPA [HR 0.63; 95% CI 0.43-0.92; p = 0.017]. Among DR4/4 subjects, rs2230199 in C3 was significantly associated [HR 3.20; 95% CI 1.75-5.85; p = 0.0002, uncorrected] a significance that withstood Bonferroni correction since it was less than 0.000833 (0.05/60) in the HLA-specific analyses. SNPs within the complement genes may contribute to IA, the first step to type 1 diabetes, with at least one SNP in C3 significantly associated with clinically diagnosed type 1 diabetes.
8.	Ask, Daniel, et al. (författare) A quadruple packer tool for conducting hydraulic stress measurements in mines and other high stress settings 2009 Ingår i: International Journal of Rock Mechanics And Mining Sciences. - : Elsevier BV. - 1365-1609 .- 1873-4545. ; 46:6, s. 1097-1102 Tidskriftsartikel (refereegranskat)
9.	Ask, D., et al. (författare) Rock stress, rock stress measurements, and the Integrated Stress Determination Method (ISDM) 2009 Ingår i: Rock Mechanics and Rock Engineering. - : Springer Science and Business Media LLC. - 0723-2632 .- 1434-453X. ; 42:4, s. 559-584 Tidskriftsartikel (refereegranskat)abstract The primary objectives of this work are to (1) improve the understanding of the prevailing stress distribution at the Äspö Hard Rock Laboratory (HRL) in SE Sweden by employing an integrated stress determination approach, and in order to accomplish this (2) extend the existing stress integration methodology denominated integrated stress determination method (ISDM; Cornet in Comprehensive Rock Engineering vol 3, Pergamon Press, Oxford, pp 413-432, 1993a). The new developments of the ISDM involve a 12-parameter representation of the regional stress field in the rock mass (i.e., the full stress tensor and its variation with depth) that is applicable to hydraulic stress data (sleeve fracturing, hydraulic fracturing, and hydraulic tests on pre-existing fractures), overcoring data (CSIR- and CSIRO-type of devices), and to combinations of hydraulic and overcoring stress data. For the latter case, the elastic parameters of the overcoring technique may be solved in situ by allowing the hydraulic stress data to constrain them. As a result, the problem then involves 14 model parameters. Results from the study show that the ISDM effectively improves the precision of the prevailing stress field determination and that it is especially powerful for identification of consistencies/inconsistencies in an existing data set. Indeed, this is the very basic premise and goal of stress integration; combine all available data to achieve as complete a characterization of the mechanical stress model as possible, and not to identify a solution that fits only loosely the maximum amount of stress data.
10.	Ask, Maria, et al. (författare) A hydraulic stress measurement system for deep borehole investigations 2017 Ingår i: Geophysical Research Abstracts. - : European Geosciences Union (EGU). - 1029-7006 .- 1607-7962. ; 19 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract Lulea University of Technology (LTU) is developing and building a wire-line system for hydraulic rock stress measurements, with funding from the Swedish Research Council and Lulea University of Technology. In this project, LTU is collaborating with University of Strasbourg and Geosigma AB. The stress state influences drilling and drillability, as well as rock mass stability and permeability. Therefore, knowledge about the state of in-situ stress (stress magnitudes, and orientations) and its spatial variation with depth is essential for many underground rock engineering projects, for example for underground storage of hazardous material (e.g. nuclear waste, carbon dioxide), deep geothermal exploration, and underground infrastructure (e.g. tunneling, hydropower dams). The system is designed to conduct hydraulic stress testing in slim boreholes. There are three types of test methods: (1) hydraulic fracturing, (2) sleeve fracturing and (3) hydraulic testing of pre-existing fractures. These are robust methods for determining in situ stresses from boreholes. Integration of the three methods allows determination of the three-dimensional stress tensor and its spatial variation with depth in a scientific unambiguously way. The stress system is composed of a downhole and a surface unit. The downhole unit consists of hydraulic fracturing equipment (straddle packers and downhole imaging tool) and their associated data acquisition systems. The testing system is state of the art in several aspects including: (1) Large depth range (3 km), (2) Ability to test three borehole dimensions (N=76 mm, H=96 mm, and P=122 mm), (3) Resistivity imager maps the orientation of tested fracture; (4) Highly stiff and resistive to corrosion downhole testing equipment; and (5) Very detailed control on the injection flow rate and cumulative volume is obtained by a hydraulic injection pump with variable piston rate, and a highly sensitive flow-meter. At EGU General Assembly 2017, we would like to present this new and unique stress measurement system and some initial test results from a 1200 m long borehole in crystalline rock
11.	Ask, Maria, et al. (författare) Detection of borehole breakouts at the Forsmark site, Sweden 2006 Ingår i: In-situ rock stress. - London : Taylor and Francis Group. - 041540097X ; , s. 79-86 Konferensbidrag (refereegranskat)abstract The objective of this paper was to investigate if borehole breakouts exist at the Forsmark investigation site of the Swedish Nuclear Fuel and Waste Management Co. Breakouts generally form when the stress concentration around the borehole exceeds the rock strength of the borehole wall, and result in borehole failure in the direction parallel to the minimum horizontal stress in vertical boreholes. Borehole televiewer and borehole image processing system data in boreholes KFM01A and KFM01B have been analyzed. The analyzes reveal that breakouts appear over 30-40% of the length of the investigated boreholes. The breakouts appear with both shallow- and deep-failure depths, where the overwhelming majority is of the shallow failure type. The scope of this initial study does not include the full characterization of identified breakouts and it is not clear at this stage as to the origin of the breakouts, i.e. if they are stress and/or drilling induced
12.	Ask, Maria, et al. (författare) Exploration for deep enhanced geothermal systems with Riksriggen and the LTU downhole stress measurement system 2017 Ingår i: 4th Sustainable Earth Sciences Conference and Exhibition 2017, Held at Near Surface Geoscience Conference and Exhibition 2017. - : European Association of Geoscientists and Engineers. - 9781510850811 ; , s. 21-25 Konferensbidrag (refereegranskat)abstract Recent developments in drilling technology have resulted in about five to ten times faster penetration rates compared to penetration rates of conventional diamond drilling. The increased penetration rates open up for affordable drilling of deep boreholes in regions with cold crust, such as in Scandinavia, allowing for geothermal energy generation in enhanced geothermal systems. We present two infrastructures for downhole sampling and testing, Riksriggen and the LTU downhole stress measurement system. Riksriggen produces a borehole that allows in-situ sampling and testing to 2.5 km depth. Furthermore, highly relevant data for geothermal energy production is produced, for example fracture geometries and frequencies, as well as depth of zones with elevated transmissivity zones and their in-situ hydraulic conductivities. The LTU downhole stress measurement system allows determination of the three-dimensional stress tensor and its spatial variation with depth in a scientific unambiguously way. Thus, Riksriggen and the LTU downhole stress measurement system provide data needed for planning most stable borehole trajectory with depth and to determine optimal pattern of production and injection wells (e.g. hydraulic stimulation by fraccing), as well as for assessing the risk of induced seismicity.
13.	Ask, Maria, et al. (författare) Project: Detection of potential borehole breakouts in boreholes 2010 Annan publikation (populärvet., debatt m.m.)abstract This project investigates the occurrence of stress-induced borehole breakouts in two boreholes at the Forsmark site, KFM01A and KFM01B, that are 500 and 1000 m deep, respectively. The primary objective was to investigate if borehole breakouts are formed in Forsmark. The results confirm the occurrence of stress-induced features, and borehole boreholes were detected between 116 and 997 m vertical depth (mvd) in the two boreholes.
14.	Ask, Maria V. S., et al. (författare) Stress Analysis in Boreholes Drag Bh and Leknes Bh, Nordland, North Norway 2015 Ingår i: Rock Mechanics and Rock Engineering. - : Springer Science and Business Media LLC. - 0723-2632 .- 1434-453X. ; 48:4, s. 1475-1484 Tidskriftsartikel (refereegranskat)abstract Nordland in northern Norway is characterized by enhanced seismicity and uplift that makes it the most tectonically active area in Norway. This study is part of a project entitled Neotectonics in Norway—Implications for Petroleum Exploration, which aims at enhancing the understanding of regional-scale stress and strain dynamics in Nordland, and to impact risk and hazard assessment and petroleum exploration. This paper attempts to constrain the orientation of in situ horizontal stress using high-resolution acoustic televiewer logging data. The Geological Survey of Norway has drilled two 0.8 km deep near-vertical boreholes on opposite sides of the Vestfjord in Nordland, the open bight of sea that separates the Lofoten archipelago from the Norwegian mainland. Both boreholes are drilled just North of 68_ N, with borehole Leknes Bh located near the geographic center of the Lofoten archipelago, and borehole Drag Bh located on approximate equal distance from the shore, on the Norwegian mainland. The results of this study are in most practical aspects inconclusive, mainly due to poor data quality. The data analysis has revealed erroneously high-borehole diameter, and several artifacts such as eccentric logging tool, rugose borehole wall, spiral hole, tool sticking and missing data. Four intervals with passive in situ stress indicators (borehole breakout and drilling-induced fractures) were found in travel time and amplitude images of the Drag Bh, suggesting approximately N–S orientation of maximum horizontal stress. However, these intervals are not found in cross-plots. Either result yields the lowest World Stress Map ranking quality (E).
15.	Watson, Hunna J., et al. (författare) Common Genetic Variation and Age of Onset of Anorexia Nervosa 2022 Ingår i: BIOLOGICAL PSYCHIATRY: GLOBAL OPEN SCIENCE. - : Elsevier BV. - 2667-1743. ; 2:4, s. 368-378 Tidskriftsartikel (refereegranskat)abstract BACKGROUND: Genetics and biology may influence the age of onset of anorexia nervosa (AN). The aims of this study were to determine whether common genetic variation contributes to age of onset of AN and to investigate the genetic associations between age of onset of AN and age at menarche.METHODS: A secondary analysis of the Psychiatric Genomics Consortium genome-wide association study (GWAS) of AN was performed, which included 9335 cases and 31,981 screened controls, all from European ancestries. We conducted GWASs of age of onset, early-onset AN (,13 years), and typical-onset AN, and genetic correlation, genetic risk score, and Mendelian randomization analyses.RESULTS: Two loci were genome-wide significant in the typical-onset AN GWAS. Heritability estimates (single nucleotide polymorphism-h2) were 0.01-0.04 for age of onset, 0.16-0.25 for early-onset AN, and 0.17-0.25 for typical-onset AN. Early-and typical-onset AN showed distinct genetic correlation patterns with putative risk factors for AN. Specifically, early-onset AN was significantly genetically correlated with younger age at menarche, and typical-onset AN was significantly negatively genetically correlated with anthropometric traits. Genetic risk scores for age of onset and early-onset AN estimated from independent GWASs significantly predicted age of onset. Mendelian randomization analysis suggested a causal link between younger age at menarche and early -onset AN.CONCLUSIONS: Our results provide evidence consistent with a common variant genetic basis for age of onset and implicate biological pathways regulating menarche and reproduction.
16.	Abdallah, J., et al. (författare) A determination of the centre-of-mass energy at LEP2 using radiative two-fermion events 2006 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:2, s. 295-305 Tidskriftsartikel (refereegranskat)abstract Using e(+)e(-) -> mu(+)mu(-)(gamma) and e(+)e(-) -> q (q) over bar(gamma) events radiative to the Z pole, DELPHI has determined the centre-of-mass energy, root s, using energy and momentum constraint methods. The results are expressed as deviations from the nominal LEP centre-of-mass energy, measured using other techniques. The results are found to be compatible with the LEP Energy Working Group estimates for a combination of the 1997 to 2000 data sets.
17.	Abdallah, J, et al. (författare) A measurement of the branching fractions of the b-quark into charged and neutral b-hadrons 2003 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 576:1-2, s. 29-42 Tidskriftsartikel (refereegranskat)abstract The production fractions of charged and neutral b-hadrons in b-quark events from Z(0) decays have been measured with the DELPHI detector at LEP. An algorithm has been developed, based on a neural network, to estimate the charge of the weakly-decaying b-hadron by distinguishing its decay products from particles produced at the primary vertex. From the data taken in the years 1994 and 1995, the fraction of (b) over bar -quarks fragmenting into positively charged weakly-decaying b-hadrons has been measured to be: f(+) = (42.09+/-0.82(stat)+/-0.89(syst))%. Subtracting the rates for charged Xi(b)(+) and Omega(b)(+) baryons gives the production fraction of B+ mesons: f(Bu) = (40.99+/-0.82(stat)+/-1.11 (syst)) %.
18.	Abdallah, J., et al. (författare) A measurement of the tau hadronic branching ratios 2006 Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:1, s. 1-26 Tidskriftsartikel (refereegranskat)abstract The exclusive and semi-exclusive branching ratios of the tau lepton hadronic decay modes (h(-)upsilon(tau), h(-)pi(0)upsilon(tau), h(-)pi(0)pi(0)upsilon(tau), h(-) >= 2 pi(0)nu(tau), 2h(-)h(+)upsilon(tau), 2h(-)h(+)>= 2 pi(0)upsilon(tau), 3h(-)2h(+)upsilon(tau) and 3h(-)2h(+) >= 1 pi(0)upsilon(tau)) were measured with data from the DELPHI detector at LEP.
19.	Abdallah, J, et al. (författare) A precise measurement of the B+, B-0 and mean b-hadron lifetime with the DELPHI detector at LEP I 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 33:3, s. 307-324 Tidskriftsartikel (refereegranskat)abstract Final results from the DELPHI Collaboration on the lifetime of B+ and B-0 mesons and the mean b-hadron lifetime, are presented using the data collected at the Z(0) peak in 1994 and 1995. Elaborate, inclusive, secondary vertexing methods have been employed to ensure a b-hadron reconstruction with good efficiency. To separate samples of B+ and B-0 mesons, high performance neural network techniques are used that achieve very high purity signals. The results obtained are: tau(B+) = 1.624+/-0.014 (stat)+/-0.018 (syst) ps tau(B)0 = 1.531+/-0.021 (stat)+/-0.031 (syst) ps tau(B+)/tau(B)0 = 1.060+/-0.021 (stat)+/-0.024 (syst) and for the average b-hadron lifetime: taub/tau(B)0 = 1.570+/-0.005 (stat)+/-0.008 (syst) ps.
20.	Abdallah, J, et al. (författare) A precise measurement of the tau lifetime 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 36:3, s. 283-296 Tidskriftsartikel (refereegranskat)abstract The tau lepton lifetime has been measured with the e(+) e(-) --> tau(+) tau(-) events collected by the DELPHI detector at LEP in the years 1991 - 1995. Three different methods have been exploited, using both one-prong and three-prong tau decay channels. Two measurements have been made using events in which both taus decay to a single charged particle. Combining these measurements gave tau(tau) ( 1 prong) = 291.8 +/- 2.3(stat) +/- 1.5(sys) fs. A third measurement using taus which decayed to three charged particles yielded tau(tau) (3 prong) = 288.6 +/- 2.4(stat) +/- 1.3(sys) fs. These were combined with previous DELPHI results to measure the tau lifetime, using the full LEP1 data sample, to be tau(tau) = 290.9 +/- 1.4(stat) +/- 1.0(sys) fs.
21.	Abdallah, J., et al. (författare) A study of b(b)over-bar production in e(+)e(-) collisions at root s=130-207 GeV 2009 Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 60:1, s. 1-15 Tidskriftsartikel (refereegranskat)abstract Measurements are presented of R-b, the ratio of the b (b) over bar cross-section to the q (q) over bar cross-section in e(+)e(-) collisions, and the forward-backward asymmetry A(FB)(b) at twelve energy points in the range root s = 130-207 GeV. These results are found to be consistent with the Standard Model expectations. The measurements are used to set limits on new physics scenarios involving contact interactions.
22.	Abdallah, J., et al. (författare) A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z Pole 2011 Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:2, s. 1557- Tidskriftsartikel (refereegranskat)abstract The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP. Two complementary methods are used to reconstruct the energy of weakly decaying b-hadrons, E-B(weak). The average value of x(B)(weak) = E-B(weak)/E-beam is measured to be 0.699 +/- 0.011. The resulting x(B)(weak) distribution is then analysed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract measurements of the non-perturbative contribution to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data: a = 1.84(-0.21)(+0.23) and b = 0.642(-0.063)(+0.073) GeV-2, with a correlation factor rho = 92.2%. Combining the data on the b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of x(B)(weak) is found to be 0.7092 +/- 0.0025 and the non-perturbative fragmentation component is extracted. Using the combined distribution, a better determination of the Lund parameters is also obtained: a = 1.48(-0.10)(+0.11) and b = 0.509(-0.023)(+0.024) GeV-2, with a correlation factor rho = 92.6%.
23.	Abdallah, J, et al. (författare) A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP 2003 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:3, s. 285-312 Tidskriftsartikel (refereegranskat)abstract Infrared and collinear safe event shape distributions and their mean values are determined in e(+)e(-) collisions at centre-of-mass energies between 45 and 202GeV. A phenomenological analysis based on power correction models including hadron mass effects for both differential distributions and mean values is presented. Using power corrections, alpha(s) is extracted from the mean values and shapes. In an alternative approach, renormalisation group invariance (RGI) is used as an explicit constraint, leading to a consistent description of mean values without the need for sizeable power corrections. The QCD beta-function is precisely measured using this approach. From the DELPHI data on Thrust, including data from low energy experiments, one finds beta(0) = 7.86 +/- 0.32 for the one loop coefficient of the beta-function or, assuming QCD, n(f) = 4.75 +/- 0.44 for the number of active flavours. These values agree well with the QCD expectation of beta(0) = 7.67 and n(f) 5. A direct measurement of the full logarithmic energy slope excludes light gluinos with a mass below 5GeV.
24.	Abdallah, J, et al. (författare) Bose-Einstein correlations in W+W- events at LEP2 2005 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 44:2, s. 161-174 Tidskriftsartikel (refereegranskat)abstract Bose-Einstein correlations (BEC) between final state particles in the reaction e(+)e(-) -> W+ W- -> q(1)(q(2)) over barq(3)(q(4)over bar>) over bar) have been studied. Data corresponding to a total integrated luminosity of 550 pb(-1), recorded by the DELPHI detector at centre-of-mass energies ranging from 189 to 209 GeV, were analysed. An indication for inter-W BEC between like-sign particles has been found at the level of 2.4 standard deviations of the combined statistical and systematic uncertainties.
25.	Abdallah, J, et al. (författare) Charged particle multiplicity in three-jet events and two-gluon systems 2005 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:44, s. 311-331 Tidskriftsartikel (refereegranskat)abstract The charged particle multiplicity in hadronic three-jet events from Z decays is investigated. The topology dependence of the event multiplicity is found to be well described by a modified leading logarithmic prediction. A parameter fit of the prediction to the data yields a measurement of the colour factor ratio C-A/C-F with the result C-A/C-F = 2.261 +/- 0.014(stat). +/- 0.036(exp). +/- 0-066(theo). in agreement with the SU(3) expectation of QCD. The quark-related contribution to the event multiplicity is subtracted from the three-jet event multiplicity resulting in a measurement of the multiplicity of two-gluon colour-singlet states over a wide energy range. The ratios r = N-gg(s)/Ng (g) over bar (s) of the gluon and quark multiplicities and r((1)) = N'(gg)(s)/N'g (g) over bar (s) of their derivatives are compared with perturbative calculations. While a good agreement between calculations and data is observed for r((1)), larger deviations are found for r indicating that non-perturbative effects are more important for r than for r((1)).
26.	Abdallah, J, et al. (författare) Coherent soft particle production in Z decays into three jets 2005 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 605:1-2, s. 37-48 Tidskriftsartikel (refereegranskat)abstract Low-energy particle production perpendicular to the event plane in three-jet events produced in Z decays in e(+)e(-) annihilation is measured and compared to that perpendicular to the event axis in two-jet events. The topology dependence of the hadron production ratio is found to agree with a leading-order QCD prediction. This agreement and especially the need for the presence of a destructive interference term gives evidence for the coherent nature of gluon radiation. Hadron production in three-jet events is found to be directly proportional to a single topological scale function of the inter-jet angles. The slope of the dependence of the multiplicity with respect to the topological scale was measured to be 2.211 +/- 0.014(stat.) +/- 0.053(syst.) in good agreement with the expectation given by the colour-factor ratio C-A/C-F = 9/4. This result strongly supports the assumption of local parton-hadron duality, LPHD, at low hadron momentum.
27.	Abdallah, J, et al. (författare) Correlations between polarisation states of W particles in the reaction e(-)e(+)-> W-W+ at LEP2 energies 189-209 GeV 2009 Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 63:4, s. 611-623 Tidskriftsartikel (refereegranskat)abstract In a study of the reaction e(-)e(+)-> W-W+ with the DELPHI detector, the probabilities of the two W particles occurring in the joint polarisation states transverse-transverse (T T), longitudinal-transverse plus transverse-longitudinal (LT) and longitudinal-longitudinal (LL) have been determined using the final states WW -> lvq (q) over bar (l = e, mu). The two-particle joint polarisation probabilities, i.e. the spin density matrix elements rho T T, rho LT, rho LL, are measured as functions of the W- production angle, theta(W-), at an average reaction energy of 198.2 GeV. Averaged over all cos.W-, the following joint probabilities are obtained: (rho) over barT T = (67 +/- 8)%, (rho) over barL T = (30 +/- 8)%, (rho) over barL T = (3 +/- 7)%. These results are in agreement with the Standard Model predictions of 63.0%, 28.9% and 8.1%, respectively. The related polarisation cross-sections sigma(TT), sigma(LT) and sigma(LL) are also presented.
28.	Abdallah, J, et al. (författare) Determination of A(FB)(b) at the Z pole using inclusive charge reconstruction and lifetime tagging 2005 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 40:1, s. 1-25 Tidskriftsartikel (refereegranskat)abstract A novel high precision method measures the b-quark forward-backward asymmetry at the Z pole on a sample of 3,560,890 hadronic events collected with the DELPHI detector in 1992 to 2000. An enhanced impact parameter tag provides a high purity b sample. For event hemispheres with a reconstructed secondary vertex the charge of the corresponding quark or anti-quark is determined using a neural network which combines in an optimal way the full available charge information from the vertex charge, the jet charge and from identified leptons and hadrons. The probability of correctly identifying b-quarks and anti-quarks is measured on the data themselves comparing the rates of double hemisphere tagged like-sign and unlike-sign events. The b-quark forward-backward asymmetry is determined from the differential asymmetry, taking small corrections due to hemisphere correlations and background contributions into account. The results for different centre-of-mass energies are: A(FB)(b) ( 89.449 GeV) = 0.0637 +/- 0.0143( stat.) +/- 0.0017( syst.), A(FB)(b) ( 91.231 GeV) = 0.0958 +/- 0.0032( stat.) +/- 0.0014( syst.), A(FB)(b) ( 92.990 GeV) = 0.1041 +/- 0.0115( stat.) +/- 0.0024( syst.). Combining these results yields the b-quark pole asymmetry A(FB)(b0) = 0.0972 +/- 0.0030( stat.) +/- 0.0014( syst.).
29.	Abdallah, J, et al. (författare) Determination of heavy quark non-perturbative parametersfrom spectral moments in semileptonic B decays 2006 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 45:1, s. 35-59 Tidskriftsartikel (refereegranskat)abstract Moments of the hadronic invariant mass and of the lepton energy spectra in semileptonic B decays have been determined with the data recorded by the DELPHI detector at LEP. From measurements of the inclusive b-hadron semileptonic decays, and imposing constraints from other measurements on b- and c-quark masses, the first three moments of the lepton energy distribution and of the hadronic mass distribution, have been used to determine parameters which enter into the extraction of vertical bar V-cb vertical bar from the measurement of the inclusive b-hadron semileptonic decay width. The values obtained in the kinetic scheme are: m(b)(1 GeV) = 4.591 +/- 0.062 +/- 0.039 +/- 0.005 GeV/c(2), m(c)(1 GeV) = 1.170 +/- 0.093 +/- 0.055 +/- 0.005 GeV/c(2), m(pi)(2) (1 GeV) = 0.399 +/- 0.048 +/- 0.034 +/- 0.087 GeV2, (p) over tilde (3)(D) = 0.053 +/- 0.017 +/- 0.011 +/- 0.026 GeV3, and include corrections at order 1/m(b)(3). Using these results, and present measurements of the inclusive semileptonic decay partial width of b-hadrons at LEP, an accurate determination of vertical bar V-cb vertical bar is obtained: vertical bar V-cb vertical bar = 0.0421 x (1 +/- 0.014 (meas center dot) +/- 0.014 (fit) +/- 0.015 (th center dot)).
30.	Abdallah, J., et al. (författare) Determination of the b quark mass at the M-Z scale with the DELPHI detector at LEP 2006 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 46:3, s. 569-583 Tidskriftsartikel (refereegranskat)abstract An experimental study of the normalized three-jet rate of b quark events with respect to light quarks events (light = l equivalent to u, d, s) has been performed using the CAMBRIDGE and DURHAM jet algorithms. The data used were collected by the DELPHI experiment at LEP on the Z peak from 1994 to 2000. The results are found to agree with theoretical predictions treating mass corrections at next-to-leading order. Measurements of the b quark mass have also been performed for both the b pole mass: M-b and the b running mass: m(b)(M-Z). Data are found to be better described when using the running mass. The measurement yields: m(b)(M-Z) = 2.85 +/- 0.18(stat) +/- 0.13(exp) +/- 0.19(had) +/- 0.12(theo) GeV/c(2). for the CAMBRIDGE algorithm. This result is the most precise measurement of the b mass derived from a high energy process. When compared to other b mass determinations by experiments at lower energy scales, this value agrees with the prediction of quantum chromodynamics for the energy evolution of the running mass. The mass measurement is equivalent to a test of the flavour independence of the strong coupling constant with an accuracy of 7 parts per thousand.
31.	Abdallah, J, et al. (författare) Determination of the e(+)e(-)->gamma gamma(gamma) cross-section at LEP 2 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 37:4, s. 405-419 Tidskriftsartikel (refereegranskat)abstract A test of the benchmark QED process e(+) e(-) -->gammagamma(gamma) is reported, using the data collected with the DELPHI detector at LEP 2. The data analysed were recorded at centre-of-mass energies ranging from 161 GeV to 208 GeV and correspond to a total integrated luminosity of 656.4 pb(-1). The Born cross-section for the process e(+) e(-)-->gammagamma(gamma) was determined, confirming the validity of QED at the highest energies ever attained in electron-positron collisions. Lower limits on the parameters of a number of possible deviations from QED, predicted within theoretical frameworks expressing physics beyond the Standard Model, were derived.
32.	Abdallah, J., et al. (författare) Di-jet production in gamma gamma collisions at LEP2 2008 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:58, s. 531-541 Tidskriftsartikel (refereegranskat)
33.	Abdallah, J., et al. (författare) Evidence for an excess of soft photons in hadronic decays of Z(0) 2006 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 47:2, s. 273-294 Tidskriftsartikel (refereegranskat)abstract Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qq disintegrations of the Z(0) were studied in the kinematic range 0.2 < E-y < I GeV and transverse momentum with respect to the closest jet direction P-T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10(-3) gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) X 10(-3) gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.
34.	Abdallah, J, et al. (författare) Final results from DELPHI on the searches for SM and MSSM neutral Higgs bosons 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 32:2, s. 145-183 Tidskriftsartikel (refereegranskat)abstract These final results from DELPHI searches for the Standard Model (SM) Higgs boson, together with benchmark scans of the Minimal Supersymmetric Standard Model (MSSM) neutral Higgs bosons, used data taken at centre-of-mass energies between 200 and 209 GeV with a total integrated luminosity of 224 pb(-1). The data from 192 to 202 GeV are reanalysed with improved b-tagging for MSSM final states decaying to four b-quarks. The 95% confidence level lower mass bound on the Standard Model Higgs boson is 114.1 GeV/c(2). Limits are also given on the lightest scalar and pseudo-scalar Higgs bosons of the MSSM.
35.	Abdallah, J, et al. (författare) Flavour independent searchesfor hadronically decaying neutral Higgs bosons 2005 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 44:2, s. 147-159 Tidskriftsartikel (refereegranskat)abstract This paper describes flavour independent searches for hadronically decaying neutral Higgs bosons in the data collected by the DELPHI experiment at LEP, at centre-of-mass energies between 189 and 209 GeV. The collected data-set corresponds to an integrated luminosity of around 610 pb(-1). The e(+)e(-) -> hA and e(+)e(-) -> hZand processes are considered, with direct Higgs boson decays into hadrons. No evidence for Higgs boson production is found, and cross-section limits are set as a function of the Higgs boson masses. No explicit assumptions are made on the underlying physics beyond the Standard Model, allowing interpretation of the data in a large class of models.
36.	Abdallah, J., et al. (författare) Higgs boson searches in CP-conserving and CP-violating MSSM scenarios with the DELPHI detector 2008 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:54, s. 1-35 Tidskriftsartikel (refereegranskat)abstract This paper presents the final interpretation of the results from DELPHI on the searches for Higgs bosons in the minimal supersymmetric extension of the Standard Model (MSSM). A few representative scenarios are considered, that include CP conservation and explicit CP violation in the Higgs sector. The experimental results encompass the searches for neutral Higgs bosons at LEP1 and LEP2 in final states as expected in the MSSM, as well as LEP2 searches for charged Higgs bosons and for neutral Higgs bosons decaying into hadrons independent of the quark flavour. The data reveal no significant excess with respect to background expectations. The results are translated into excluded regions of the parameter space in the various scenarios. In the CP-conserving case, these lead to limits on the masses of the lightest scalar and pseudoscalar Higgs bosons, h and A, and on tan beta. The dependence of these limits on the top quark mass is discussed. Allowing for CP violation reduces the experimental sensitivity to Higgs bosons. It is shown that this effect depends strongly on the values of the parameters responsible for CP violation in the Higgs sector.
37.	Abdallah, J, et al. (författare) Inclusive b decays to wrong sign charmed mesons 2003 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 561:1-2, s. 26-40 Tidskriftsartikel (refereegranskat)abstract The production of wrong sign charmed mesons b --> (D) over bar X-(s), D-(s) = (D-0, D+, D-s), is studied using the data collected by the DELPHI experiment in the years 1994 and 1995. Charmed mesons in Z --> b (b) over bar events are exclusively reconstructed by searching for the decays D-0 --> K(-)pi(+), D+ --> K(-)pi(+)pi(+) and D-s(+) --> phipi(+) --> K(+)K(-)pi(+). The wrong sign contribution is extracted by using two discriminant variables: the charge of the b-quark at decay time, estimated from the charges of identified particles, and the momentum of the charmed meson in the rest frame of the b-hadron. The inclusive branching fractions of b-hadrons into wrong sign charm mesons are measured to be: B(b --> (D) over bar X-0) + B(b --> D-X) = (9.3 +/- 1.7(stat) +/- 1.3(syst) +/- 0.4(B))%, B(b --> Ds-X) = (10.1 +/- 1.0(stat) +/- 0.6(syst) +/- 2.8(B))% where the first error is statistical, the second and third errors are systematic. (C) 2003 Published by Elsevier Science B.V.
38.	Abdallah, J, et al. (författare) Inclusive single-particle production in two-photon collisions at LEP II with the DELPHI detector 2009 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 678:5, s. 444-449 Tidskriftsartikel (refereegranskat)abstract A study of the inclusive charged hadron production in two-photon collisions is described. The data were collected with the DELPHI detector at LEP II. Results on the inclusive single-particle p(T) distribution and the differential charged hadrons d sigma/dp(T) cross-section are presented and compared to the predictions of perturbative NLO QCD calculations and to published results. (C) 2009 Elsevier B.V. All rights reserved.
39.	Abdallah, J., et al. (författare) Investigation of colour reconnection in WW events with the DELPHI detector at LEP-2 2007 Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 51:2, s. 249-269 Tidskriftsartikel (refereegranskat)abstract In the reaction e(+)e(-) -> WW -> (q(1) (q) over bar (2))(q(3)(q) over bar (4)) the usual hadronization models treat the colour singlets q(1)(q) over bar (2) and q(3)(q) over bar (4) coming from two W bosons independently. However, since the. nal state partons may coexist in space and time, cross-talk between the two evolving hadronic systems may be possible during fragmentation through soft gluon exchange. This e. ect is known as colour reconnection. In this article the results of the investigation of colour reconnection e. ects in fully hadronic decays of W pairs in DELPHI at LEP are presented. Two complementary analyses were performed, studying the particle. ow between jets and W mass estimators, with negligible correlation between them, and the results were combined and compared to models. In the framework of the SK-I model, the value for its. parameter most compatible with the data was found to be: (SK)-S-kappa-I = 2.2(-1.3) (+2.5) corresponding to the probability of reconnection P-reco to be in the range 0.31 < P-reco < 0.68 at 68% confidence level with its best value at 0.52.
40.	Abdallah, J., et al. (författare) Masses, lifetimes and production rates of Xi(-) and Xi(+) at LEP 1 2006 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 639:3-4, s. 179-191 Tidskriftsartikel (refereegranskat)abstract Measurements of the Xi(-) and (Xi) over bar (+) masses, mass differences, lifetimes and lifetime differences are presented. The (Xi) over bar (+) sample used is much larger than those used previously for such measurements. In addition, the S production rates in Z -> b (b) over bar and Z -> q (q) over bar events are compared and the position xi* of the maximum of the distribution in Z -> q (q) over bar events is measured.
41.	Abdallah, J., et al. (författare) Measurement and interpretation of fermion-pair production at LEP energies above the Z resonance 2006 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 45:3, s. 589-632 Tidskriftsartikel (refereegranskat)abstract This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e(+)e(-) -> f (f) over bar process for centre-of-mass energies above the Z resonance, from root s similar to 130-207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e(+)e(-) -> f (f) over bar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of (v) over tilde in R-parity violating supersymmetry.
42.	Abdallah, J, et al. (författare) Measurement of inclusive f(1) (1285) and f(1) (1420) production in Z decays with the DELPHI detector 2003 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 569:3-4, s. 129-139 Tidskriftsartikel (refereegranskat)abstract DELPHI results are presented on the inclusive production of two (K(K) over bar π)(0) states in the mass region 1.2-1.6 GeV/c(2) in hadronic Z decays at LEP I. The measured masses (widths) are 1274 +/- 6 MeV/c(2) (29 +/- 12 MeV/c(2)) and 1426 +/- 6 MeV/c(2) (51 +/- 14 MeV/c(2)), respectively. A partial-wave analysis of the (K(K) over bar π)(0) system shows that the first peak is consistent with the I-G (J(PC)) = 0(+)(1(++))/(0(-+))a(0)(980)pi and the second with the I-G (J(PC)) = 0(+)(1(++))K*(892)(K) over bar + c.c. assignments. The total hadronic production rates per hadronic Z decay are (0.165 +/- 0.051) and (0.056 +/- 0.012), respectively. These measurements are consistent with the two states being the f(1) (1285) and f(1) (1420) mesons. (C) 2003 Published by Elsevier B.V.
43.	Abdallah, J, et al. (författare) Measurement of the e(+)e(-)-> W+W- gamma cross-section and limits on anomalous quartic gauge couplings with DELPHI 2003 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 31:2, s. 139-147 Tidskriftsartikel (refereegranskat)abstract W(+)W(-)gamma production at LEP2 is studied using data collected with the DELPHI detector at centre-of-mass energies between 189 GeV and 209 GeV, corresponding to an integrated luminosity of about 600 pb(-1). Cross-sections are measured for the production of W+W- with a hard, central and isolated photon in the final state, and are found to be compatible with the Standard Model prediction. The photon energy spectra are used to derive limits on anomalous contributions to the W(+)W(-)Z(o)gamma and W(+)W(-)gammagamma vertices.
44.	Abdallah, J., et al. (författare) Measurement of the electron structure function F-2(e) at LEP energies 2014 Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 737, s. 39-47 Tidskriftsartikel (refereegranskat)abstract The hadronic part of the electron structure function F-2(e) has been measured for the first time, using e(+)e(-) data collected by the DELPHI experiment at LEP, at centre-of-mass energies of root s = 91.2-209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F-2(e) data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F-2(gamma) analyses and help in refining existing parameterisations.
45.	Abdallah, J, et al. (författare) Measurement of the energy dependence of hadronic jet rates and the strong coupling alpha(s) from the four-jet rate with the DELPHI detector at LEP 2005 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 38:4, s. 413-426 Tidskriftsartikel (refereegranskat)abstract Hadronic events from the data collected with the DELPHI detector at LEP within the energy range from 89 GeV to 209 GeV are selected, their jet rates are determined and compared to predictions of four different event generators. One of them is the recently developed APACIC++ generator which performs a massive matrix element calculation matched to a parton shower followed by string fragmentation. The four-jet rate is used to measure alpha(s) in the next-to-leading-order approximation yielding alpha(s)(M-Z(2)) = 0.1175 +/- 0.0030. The running of alpha(s) determined by using four-jet events has been tested. The logarithmic energy slope is measured to be dalpha(s)(-1)/d log E-cm = 1.14 +/- 0.36. Since the analysis is based on four-jet final states it represents an alternative approach to previous DELPHI alpha(s) measurements using event shape distributions.
46.	Abdallah, J, et al. (författare) Measurement of the forward-backward asymmetries of e(+)e(-)-> Z -> b(b)over-bar and e(+)e(-)-> Z -> c(c)over-bar using prompt leptons 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 34:2, s. 109-125 Tidskriftsartikel (refereegranskat)abstract The forward-backward asymmetries of the processes e(+) e(-) --> Z --> b (b) over bar and e(+)e(-) --> Z --> c (c) over bar were measured from a sample of hadronic Z decays collected by the DELPHI experiment between 1993 and 1995. Enriched samples of b (b) over bar and c (c) over bar events were obtained using lifetime information. The tagging of b and c quarks in these samples was based on the semileptonic decay channels b/c --> X + mu and b/c --> X + e combined with charge flow information from the hemisphere opposite to the lepton. Combining the A(FB)(b (b) over bar) and A(FB)(c (c) over bar) measurements presented in this paper with published results based on 1991 and 1992 DELPHI data samples, the following pole asymmetries were obtained: A(FB)(0,b) = 0.1021 +/- 0.0052 (stat) +/- 0.0024 (syst) A(FB)(0,c) = 0.0728 +/- 0.0086 (stat) +/- 0.0063 (syst) The effective value of the weak mixing angle derived from these measurements is sin(2) theta(W,eff)(lept) = 0.23170 +/- 0.00097.
47.	Abdallah, J, et al. (författare) Measurement of the Lambda(0)(b) decay form factor 2004 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 585:1-2, s. 63-84 Tidskriftsartikel (refereegranskat)abstract The form factor of A(o)(b) baryons is estimated using 3.46 x 10(6) hadronic Z decays collected by the DELPM experiment between 1992 and 1995. Charmed A(c)(+) baryons fully reconstructed in the pK(-)pi(+), pK(o)(s), and Api(+)pi(+)pi(-) modes, are associated to a c S lepton with opposite charge in order to select A(o)(b) --> A(c)(+)l(-)v(l) decays. From a combined likelihood and event rate fit to the b C distribution of the Isgur-Wise variable w, and using the Heavy Quark Effective Theory (HQET), the slope of the b-baryon form factor is measured to be p(2)=2.03+/-0.46(stat)(-1.00)(+0.72)(syst). The exclusive semileptonic branching fraction Br(A(b)(o) --> A(c)(+)l(-)v(l)) can be derived from p(2) and is found to be (5.0(-0.8)(+1.1)(stat)(-1.2)(+1.6) (syst))%. Limits on other branching fractions are also obtained. (C) 2004 Published by Elsevier B.V.
48.	Abdallah, J., et al. (författare) Measurement of the mass and width of the W boson in e(+) e(-) collisions at root s=161-209 GeV 2008 Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; C:55, s. 1-38 Tidskriftsartikel (refereegranskat)abstract A measurement of the W boson mass and width has been performed by the DELPHI collaboration using the data collected during the full LEP2 programme (1996-2000). The data sample has an integrated luminosity of 660 pb(-1) and was collected over a range of centre-of-mass energies from 161 to 209 GeV. Results are obtained by applying the method of direct reconstruction of the mass of the W from its decay products in both the W+W- -> l (nu) over bar (l) and W+W- -> q (q) over bar'(q) over barq'channels. The W mass result for the combined data set is M-W = 80.336 +/- 0.055(Stat.) +/- 0.028(Syst.) +/- 0.025(FSI) +/- 0.009(LEP) GeV/c(2) , where FSI represents the uncertainty due to final state interaction effects in the q (q) over bar'(q) over barq' channel, and LEP represents that arising from the knowledge of the collision energy of the accelerator. The combined value for the W width is Gamma(W) = 2.404 +/- 0.140(Stat.) +/- 0.077(Syst.) +/- 0.065(FSI) GeV/c(2). These results supersede all values previously published by the DELPHI collaboration.
49.	Abdallah, J., et al. (författare) Measurement of the tau lepton polarisation at LEP2 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 659:1-2, s. 65-73 Tidskriftsartikel (refereegranskat)abstract A first measurement of the average polarisation P-tau of tau leptons produced in e(+)e(-) annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P-tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV. (c) 2007 Elsevier B.V. All rights reserved.
50.	Abdallah, J, et al. (författare) Measurement of the W-pair production cross-section and W branching ratios in e(+)e(-) collisions at root s=161-209 GeV 2004 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 34:2, s. 127-144 Tidskriftsartikel (refereegranskat)abstract These final results on e(+) e(-) W+ W- production cross-section measurements at LEP2 use data collected by the DELPHI detector at centre-of-mass energies up to 209 GeV. Measurements of total cross-sections, W angular differential distributions and decay branching fractions, and the value of the CKM element \|V-cs\| are compared to the expectations of the Standard Model. These results supersede all values previously published by DELPHI.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "WFRF:(Ask Maria) "

Avgränsa träffmängd

År