| 1. |
- Abazov, V. M., et al.
(författare)
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Study of the decay Bs0→J/ψf2′(1525) in μ +μ -K +K - final states
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:9, s. 092011-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the decay Bs0→J/ψK +K - for invariant masses of the K +K - pair in the range 1.35<M(K +K -)<2GeV. The data sample corresponds to an integrated luminosity of 10.4fb -1 of pp̄ collisions at √s=1.96TeV accumulated with the D0 detector at the Fermilab Tevatron collider. From the study of the invariant mass and spin of the K +K - system, we find evidence for the two-body decay Bs0→J/ψf2′(1525) and measure the relative branching fraction of the decays Bs0→J/ψf2′(1525) and Bs0→J/ψ to be R f2′/=0.19±0.05(stat)±0.04(syst).
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| 2. |
- Aaltonen, T., et al.
(författare)
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Combination of CDF and D0 measurements of the W boson helicity in top quark decays
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:7, s. 071106-
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Tidskriftsartikel (refereegranskat)abstract
- We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7-5.4 fb(-1) of p (p) over bar collisions collected during Run II of the Fermilab Tevatron collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f(0)) and right-handed (f(+)) helicities, we find f(0) = 0.722 +/- 0.081[+/- 0.062(stat) +/- 0.052(syst)] and f(+) = -0.033 +/- 0.046[+/- 0.034(stat) +/- 0.031(syst)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f(0) = 0.682 +/- 0.057[+/- 0.035(stat) +/- 0.046(syst)] for fixed f(+) and f(+) = -0.015 +/- 0.035[+/- 0.018(stat) +/- 0.030(syst)] for fixed f(0). The results are consistent with standard model expectations.
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| 3. |
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| 4. |
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| 5. |
- Aaltonen, T., et al.
(författare)
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Combination of the top-quark mass measurements from the Tevatron collider
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:9, s. 092003-
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Tidskriftsartikel (refereegranskat)abstract
- The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a W boson and a bottom quark. Using top-antitop pairs at the Tevatron proton-antiproton collider, the CDF and D0 Collaborations have measured the top quark's mass in different final states for integrated luminosities of up to 5.8fb -1. This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is 173.18±0.56(stat)±0.75(syst)GeV or 173.18±0.94GeV, which has a precision of ±0.54%, making this the most precise determination of the top-quark mass.
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| 6. |
- Aaltonen, T., et al.
(författare)
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Search for neutral Higgs bosons in events with multiple bottom quarks at the Tevatron
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:9, s. 091101-
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Tidskriftsartikel (refereegranskat)abstract
- The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb(-1) of integrated luminosity at CDF and 5.2 fb(-1) at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example, in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.
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| 7. |
- Aaltonen, T., et al.
(författare)
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Combination of measurements of the top-quark pair production cross section from the Tevatron Collider
- 2014
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:7
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Tidskriftsartikel (refereegranskat)abstract
- We combine six measurements of the inclusive top-quark pair (t(sic)) production cross section (sigma(t)(sic)) from data collected with the CDF and D0 detectors at the Fermilab Tevatron with proton-antiproton collisions at root s = 1.96 TeV. The data correspond to integrated luminosities of up to 8.8 fb(-1). We obtain a value of sigma tt = 7.60 +/- 0.41 pb for a top-quark mass of m(t) = 172.5 GeV. The contributions to the uncertainty are 0.20 pb from statistical sources, 0.29 pb from systematic sources, and 0.21 pb from the uncertainty on the integrated luminosity. The result is in good agreement with the standard model expectation of 7.35(-0.33)(+0.28) pb at next-to-next-to-leading order and next-to-next-to leading logarithms in perturbative QCD.
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| 8. |
- Colins, Olivier F., 1978-, et al.
(författare)
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Psychiatric disorder in detained male adolescents as risk factor for serious recidivism
- 2011
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Ingår i: Canadian journal of psychiatry. - : Sage Publications. - 0706-7437 .- 1497-0015. ; 56:1, s. 44-50
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: A growing body of research consistently shows that detained minors bear substantial mental health needs. However, the relation between mental disorder and criminal recidivism has largely remained unexplored. Our study examines whether psychiatric disorders increase the likelihood of recidivism after controlling for time at risk, criminal history, and the presence of other disorders.METHOD: Participants (n = 232) were detained male adolescents from all 3 youth detention centres in Flanders, Belgium, who were interviewed with the Diagnostic Interview Schedule for Children, Version IV. Two to 4 years later, information on serious recidivism was retrieved from the official judicial registration system. Serious recidivism was defined as having at least one arrest charge for violent, severe property crime, or substance-related offences.RESULTS: Serious recidivism was high, with 81% (n = 191) of the participants being rearrested. Psychiatric disorders predicted neither serious recidivism in general nor violent and severe property recidivism. However, other drug use disorder (OR 2.41; 95% CI 1.22 to 4.75) and general comorbidity (OR 2.64; 95% CI 1.40 to 4.99) were significantly predictive of substance-related recidivism.CONCLUSION: Common psychiatric disorders in detained male adolescents do not significantly increase the likelihood of subsequent arrests, with the exception that substance use disorders appear to increase the risk of later substance-related recidivism. Effective treatment of these disorders may prevent detained juveniles to experience the detrimental outcomes associated with substance-related crimes as adults (for example, mental illness).
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| 9. |
- Ernens, Dennis, et al.
(författare)
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On the Sealability of Metal-to-Metal Seals With Application to Premium Casing and Tubing Connections
- 2019
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Ingår i: SPE Drilling & Completion. - : Society of Petroleum Engineers. - 1064-6671 .- 1930-0204. ; 34:4, s. 382-396
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Tidskriftsartikel (refereegranskat)abstract
- Metal-to-metal seals are used in connections of casing and tubing in oil and gas wells. This paper describes the mechanisms of sealing metal-to-metal seals as investigated using an experimental setup and a stochastic numerical sealing model. Experiments were conducted for a variety of thread compounds and applied pin/box surface coatings. The results were used to validate a stochastic numerical sealing model for sealability. The model couples a contact-mechanics model with a flow model and takes into account the influence of all the surface-topography features by introducing the concept of seal permeability. Once validated, the model was used together with the experimental results to better understand the sealing mechanisms of metal-to-metal seals.The sealing configuration is a face seal with an 80-mm roundoff radius on one face pressing against a flat on the other face. The face-seal specimens were manufactured from P110 tubing to ensure material properties that are representative for casing or tubing. The test setup used is designed for investigating only the metal-to-metal seal of the connection. The setup can perform rotary sliding under constant load to simulate surface changes during makeup and subsequently perform a leakage test. The sealing limit is determined by applying 700-bar fluid pressure and then gradually reducing the normal force until leakage is observed. The data are subsequently used to validate the previously published stochastic numerical sealing model.The results indicate a strong dependence on the type of thread compound used for the onset of leakage. The thread compound affects the amount of wear and thus changes the surface topography of the interacting surfaces. It is shown that the stochastic numerical sealing model is capable of predicting the onset of leakage within the experimental accuracy. The model shows further that certain surface topographical features improve the sealing performance. In particular, a surface manufactured by turning on a lathe that is in contact with, for instance, a smooth shot-blasted surface topography leads to highly localized contact areas, which in turn yield the best sealing performance.
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| 10. |
- Sindi, Shireen, et al.
(författare)
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Midlife work-related stress is associated with late-life cognition
- 2017
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Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 264:9, s. 1996-2002
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the associations between midlife work-related stress and late-life cognition in individuals without dementia from the general population. The Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study population (n = 2000) was randomly selected from independent Finnish population-based surveys (baseline mean age 50 years). Participants underwent two re-examinations in late life (mean age 71 and 78 years, respectively). 1511 subjects participated in at least one re-examination (mean total follow-up 25 years). Work-related stress was measured using two questions on work demands administered in midlife. Multiple cognitive domains were assessed. Analyses were adjusted for several potential confounders. Higher levels of midlife work-related stress were associated with poorer performance on global cognition [beta-coefficient, -0.02; 95% confidence interval (CI), -0.05 to -0.00], and processing speed [beta -0.03, CI -0.05 to -0.01]. Results remained significant after adjusting for potential confounders. Work-related stress was not significantly associated with episodic memory, executive functioning, verbal fluency or manual dexterity. This study shows that global cognition and processing speed may be particularly susceptible to the effects of midlife work-related stress.
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