| 1. |
- 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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| 4. |
- Hannelius, U, et al.
(författare)
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Large-scale zygosity testing using single nucleotide polymorphisms
- 2007
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Ingår i: Twin research and human genetics : the official journal of the International Society for Twin Studies. - : Cambridge University Press (CUP). - 1832-4274. ; 10:4, s. 604-625
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Tidskriftsartikel (refereegranskat)abstract
- A requirement for performing robust genetic and statistical analyses on twins is correctly assigned zygosities. In order to increase the power to detect small risk factors of disease, zygosity testing should also be amenable for high throughput screening. In this study we validate and implement the use of a panel of 50 single nucleotide polymorphisms (SNPs) for reliable high throughput zygosity testing and compare it to a panel of 16 short tandem repeats (STRs). We genotyped both genomic (gDNA) and whole genome amplified DNA (WGA DNA), ending up with 47 SNP and 11 STR markers fulfilling our quality criteria. Out of 99 studied twin pairs, 2 were assigned a different zygosity using SNP and STR data as compared to self reported zygosity in a questionnaire. We also performed a sensitivity analysis based on simulated data where we evaluated the effects of genotyping error, shifts in allele frequencies and missing data on the qualitative zygosity assignments. The frequency of false positives was less than 0.01 when assuming a 1% genotyping error, a decrease of 10% of the observed minor allele frequency compared to the actual values and up to 10 missing markers. The SNP markers were also successfully genotyped on both gDNA and WGA DNA from whole blood, saliva and filter paper. In conclusion, we validate a robust panel of 47 highly multiplexed SNPs that provide reliable and high quality data on a range of different DNA templates.
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