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- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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- McLafferty, Robert B., et al.
(författare)
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Increasing awareness about venous disease: The American Venous Forum expands the National Venous Screening Program
- 2008
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Ingår i: Journal of Vascular Surgery. - : Elsevier BV. - 1097-6809 .- 0741-5214. ; 48:2, s. 394-399
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the results of the expanded National Venous Screening Program (NVSP) as administered by the American Venous Forum. Methods. Eighty-three physicians across 40 states participated in screening Americans for venous disease. The NVSP instrument included demographics, venous thromboembolism (VTE) risk assessment, quality-of-life (QOL) assessment, duplex ultrasound scan for reflux and obstruction, and clinical inspection. Participants received educational materials and a report card to give their physician. Results: A total of 2234 individuals underwent screening (mean, 26 people/site; range, 4-42). Demographic data observed included mean age of 60 years (range, 17-93 years); 77% female; 80% Caucasian; mean BMI of 29 (range, 11-68); 40% current or previous smoker; and 24% taking antiplatelet therapy and 4% taking warfarin. If placed in a situation conducive for VTE, 40% of participants were low risk, 22% were moderate risk, 21% were high risk, and 17% were very high risk. On a venous QOL assessment, 17% had a combined total score for all 11 questions of "very limited" or "impossible to do." Reflux or obstruction was noted in 37% and 5% of participants, respectively. CEAP class 0 to 6 was 29%, 29%, 23%, 10%, 9%, 1.5%, 0.5%, respectively. Discussion: Despite a dramatic expansion in the second annual NSVP (from 17 to 83 centers), the presence of venous disease observed in a larger screened population continues to be high. The NVSP represents one pathway to increasing public awareness about venous disease.
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