151 research outputs found

    Luminosity Measurement in the L3 Detector at LEP

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    One of the limiting factors in the determination of the electroweak parameters from cross section measurements of e+e- annihilation close to the Z pole is the precision of the luminosity measurement. The luminosity monitor of the L3 detector at LEP and the analysis of its data are described. Using a combination of a BGO calorimeter and a 3-layer silicon tracker, the absolute luminosity has been measured with an experimental precision of 0.08% in 1993 and 0.05% in 1994. The measurement relies on a detailed understanding of small-angle elastic e+e-(Bhabha) scattering from the experimental and theoretical point of view, as well as an excellent knowledge of the detector geometry

    Search For Exotic Tau-decays

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    The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes tau -> e gamma, tau -> e pi0, tau -> e eta. No signal was observed. We obtained the following 90% CL upper limits on the branching fractions:B(tau -> e gamma)< 2.0x10^(-4),B(tau -> e pi0) < 1.4x10^(-4),B(tau -> e eta) < 2.4x10^(-4)

    A controlled study of supplementation with essential amino acids and α-keto acids in the conservative management of patients with chronic renal failure

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    Art und Zusammensetzung einer optimalen eiweißarmen ErnĂ€hrung fĂŒr Patienten mit Niereninsuffizienz sind weiterhin umstritten. Die orale medikamentöse Behandlung mit essentiellen AminosĂ€uren oder α-KetosĂ€uren wird hĂ€ufig empfohlen. Unsere Untersuchungen vergleichen nacheinander bei 15 ambulanten Patienten mit chronischem Nierenversagen (mittlere Kreatinin-Clearance 10,8 ml/min) unter einer eiweißarmen ErnĂ€hrung von 0,57 g/kg Körpergewicht (40 g/70 kg) die Wirkung einer Substitution mit essentiellen AminosĂ€uren, danach die Substitution mit α-KetosĂ€uren gegenĂŒber Plazebo. Der nachgewiesene Proteingehalt in der Nahrung betrug 0,55 g/kg, die Energiezufuhr 27 kcal/kg Körpergewicht, wie mehrfach ErnĂ€hrungsprotokolle ĂŒber jeweils 7 Tage bei den Patienten zeigen ließen. Nach einer Vorperiode von 6 Wochen nur unter diĂ€tetischen Maßnahmen erhielten alle Patienten zusĂ€tzlich 0,112 g essentielle AminosĂ€uren/kg Körpergewicht ĂŒber 6 Wochen, danach in einer Doppelblinduntersuchung 0,105 g α-KetosĂ€uren/kg Körpergewicht im Vergleich gegenĂŒber Plazebo, ebenfalls jeweils ĂŒber 6 Wochen. NĂŒchtern-Blutuntersuchungen wurden fĂŒr ein Standard-Laborwertprogramm, insbesondere fĂŒr 15 Proteinmangelparameter, alle 3 Wochen durchgefĂŒhrt, ferner anthropometrische und klinische Kontrollen. Die Laborwerte erbrachten keine Hinweise auf einen manifesten Proteinmangel. Die Therapie mit α-KetosĂ€uren erniedrigte die Phosphatspiegel signifikant (p<0,05). Dagegen konnten weder unter essentiellen AminosĂ€uren oder α-KetosĂ€uren andere fĂŒr den Patienten wesentliche Effekte nachgewiesen werden. Deshalb erscheint uns eine Substitution mit essentiellen AminosĂ€uren oder KetosĂ€uren ĂŒberflĂŒssig bei Patienten mit einer chronischen Niereninsuffizienz, die sich in einem stabilen Stoffwechselgleichgewicht befinden und mit einer Eiweißzufuhr von 0,55 g/kg Körpergewicht behandelt werden. Oral therapy with essential amino acids (EAA) or α-keto acids (α-KA) has been recommended in patients with renal failure, but quality and quantity of optimal protein intake are still controversial. This study compares sequentially the effect of supplementation with EAA, and with α-KA versus placebo in 15 ambulatory patients with chronic renal failure (average creatinine clearance 10.8 ml/min), maintained on a protein diet of 0.57 g/kg body weight (40 g for a 70-kg patient). The actual dietary intake averaged 0.55 g protein/kg and 27 kcal/kg according to repeated 7-day dietary recordings. After a 6-week baseline period on this diet, all patients received additionally 0.112 g EAA/kg for 6 weeks followed by a double-blind cross-over study of 0.105 g α-KA/kg versus placebo supplementation for 6 weeks each. Fasting blood samples for multiple parameters, including 15 indicators for protein deficiency, as well as anthropometric and clinical data were evaluated every 3 weeks. Laboratory data revealed no indications of protein deficiency. Therapy with α-KA diminished serum phosphate concentration (p<0.05), however no other significant beneficial effects could be demonstrated during supplementation with either EAA or α-KA. Therefore, such supplementation to a 0.55-g/kg-protein diet appears superfluous in stable ambulatory patients with renal insufficiency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41743/1/394_2005_Article_BF02020747.pd

    A determination of electroweak parameters from Z0→Ό+ÎŒ- (Îł)

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    Measurement of electroweak parameters from hadronic and leptonic decays of the Z 0

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    We have studied the reactions e + e − →hadrons, e + e − , ÎŒ + ÎŒ − and τ + τ − , in the energy range 88.2 GeV. A total luminosity of 5.5 pb −1 , corresponding to approximately 115000 hadronic and 10000 leptonic Z 0 decays, has been recorded with the L3 detector. From a simultaneous fit to all of our measured cross section data, we obtain assuming lepton universality:Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47890/1/10052_2005_Article_BF01475788.pd

    УпраĐČĐ»Đ”ĐœĐžĐ” ŃĐžŃŃ‚Đ”ĐŒĐŸĐč ŃĐ»Đ”ĐșŃ‚Ń€ĐŸŃ…ĐžĐŒĐžŃ‡Đ”ŃĐșĐŸĐč защОты ĐŒĐ°ĐłĐžŃŃ‚Ń€Đ°Đ»ŃŒĐœĐŸĐłĐŸ ĐłĐ°Đ·ĐŸĐżŃ€ĐŸĐČĐŸĐŽĐ° ĐČ ŃƒŃĐ»ĐŸĐČоях ĐČĐ”Ń‡ĐœĐŸĐč ĐŒĐ”Ń€Đ·Đ»ĐŸŃ‚Ń‹

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    ОбъДĐșŃ‚ĐŸĐŒ ĐžŃŃĐ»Đ”ĐŽĐŸĐČĐ°ĐœĐžŃ ĐżĐŸĐŽŃĐžŃŃ‚Đ”ĐŒĐ° ĐșĐŸŃ€Ń€ĐŸĐ·ĐžĐŸĐœĐœĐŸĐłĐŸ ĐŒĐŸĐœĐžŃ‚ĐŸŃ€ĐžĐœĐłĐ° ŃĐ»Đ”ĐșŃ‚Ń€ĐŸŃ…ĐžĐŒĐžŃ‡Đ”ŃĐșĐŸĐč Đ·Đ°ŃˆĐžŃ‚Ń‹ ĐŒĐ°ĐłĐžŃŃ‚Ń€Đ°Đ»ŃŒĐœĐŸĐłĐŸ ĐłĐ°Đ·ĐŸĐżŃ€ĐŸĐČĐŸĐŽĐ°. ĐŠĐ”Đ»ŃŒ Ń€Đ°Đ±ĐŸŃ‚Ń‹ – ĐżŃ€ĐŸĐ°ĐœĐ°Đ»ĐžĐ·ĐžŃ€ĐŸĐČать упраĐČĐ»Đ”ĐœĐžĐ” ŃĐžŃŃ‚Đ”ĐŒĐŸĐč ŃĐ»Đ”ĐșŃ‚Ń€ĐŸŃ…ĐžĐŒĐžŃ‡Đ”ŃĐșĐŸĐč Đ·Đ°ŃˆĐžŃ‚Ń‹ ĐŒĐ°ĐłĐžŃŃ‚Ń€Đ°Đ»ŃŒĐœĐŸĐłĐŸ ĐłĐ°Đ·ĐŸĐżŃ€ĐŸĐČĐŸĐŽĐ° ĐČ ŃƒŃĐ»ĐŸĐČоях ĐČĐ”Ń‡ĐœĐŸĐč ĐŒĐ”Ń€Đ·Đ»ĐŸŃ‚Ń‹. В Ń€Đ”Đ·ŃƒĐ»ŃŒŃ‚Đ°Ń‚Đ” Đ°ĐœĐ°Đ»ĐžĐ·Đ° ŃƒŃŃ‚Đ°ĐœĐŸĐČĐ»Đ”ĐœĐŸ, Ń‡Ń‚ĐŸ ПКМ-йХй-ĐšĐŸĐœŃ‚ĐšĐŸŃ€Ń€ ŃƒĐŽĐŸĐČлДтĐČĐŸŃ€ŃĐ”Ń‚ Ń‚Ń€Đ”Đ±ĐŸĐČĐ°ĐœĐžŃĐŒ ŃĐžŃŃ‚Đ”ĐŒŃ‹ упраĐČĐ»Đ”ĐœĐžŃ Ń‚Đ”Ń…ĐœĐžŃ‡Đ”ŃĐșĐžĐŒ ŃĐŸŃŃ‚ĐŸŃĐœĐžĐ”ĐŒ Đž Ń†Đ”Đ»ĐŸŃŃ‚ĐœĐŸŃŃ‚ŃŒŃŽ ĐżĐ»ĐŸŃ‰Đ°ĐŽĐœŃ‹Ń… ĐŸĐ±ŃŠĐ”ĐșŃ‚ĐŸĐČ ĐŸŃ€ĐłĐ°ĐœĐžĐ·Đ°Ń†ĐžĐž.The object of study is the subsystem of corrosion monitoring of electrochemical protection of the main gas pipeline. The purpose of the work is to analyze the management of the system of electrochemical protection of the main gas pipeline in permafrost conditions. As a result of the analysis, it was established that PKM-TST-KontKorr satisfies the requirements of the system for managing the technical condition and integrity of the organization’s area facilities

    Measurement of Z0 decays to hadrons, and a precise determination of the number of neutrino species

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    We have made a precise measurement of the cross section for e+e---&gt;Z0--&gt;hadrons with the L3 detector at LEP, covering the range from 88.28 to 95.04 GeV. From a fit to the Z0 mass, total width, and the hadronic cross section to be MZ0=91.160 +/- 0.024 (experiment) +/-0.030(LEP) GeV, [Gamma]Z0=2.539+/-0.054 GeV, and [sigma]h(MZ0)=29.5+/-0.7 nb. We also used the fit to the Z0 peak cross section and the width todetermine [Gamma]invisible=0.548+/-0.029 GeV, which corresponds to 3.29+/-0.17 species of light neutrinos. The possibility of four or more neutrino flavors is thus ruled out at the 4[sigma] confidence level.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28683/3/0000500.pd

    A measurement of the Z0 leptonic partial widths and the vector and axial vector coupling constants

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    We have measured the partial widths of the Z0 into lepton pairs, and the forward-backward charge asymmetry for the process e+e---&gt;[mu]+[mu]- using the L3 detector at LEP. We obtain an average [Gamma]ll of 83.0+/-2.1+/-1.1 MeV.From this result and the asymmetry measurement, we extract the values of the vector and axial vector couplings of the Z0 to leptons: grmv=-0.066-0.027+0.046 and grmA= -0.495-0.007+0.007.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28666/3/0000483.pd

    Test of QED in e+e−→γγ at LEP

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    Search for excited taus from Z0 decays

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