1,720,967 research outputs found
Measurement of the Mass of the
No full textThe mass of the Z boson has been determined by combining the data from the four LEP experiments ALEPH, DELPHI, L3 and OPAL. The dominant error arises from uncertainties in the calibration of the energy of the beams in LEP. A programme of investigations including energy calibration by resonant depolarization of transversely polarized beams has led to a significant reduction of the uncertainty on the Z mass compared with the precision achieved with the 1990 data. The mass of the Z is measured to be M Z = (91:187 \Sigma 0:007) GeV. (subm. to Phys. Lett. B) 1) Author list see [1] 2) Lists of authors can be found in the references listed under [2] 1 Introduction The mass, M Z , of the neutral weak boson is a fundamental parameter of nature and the large electron-positron collider, LEP, at CERN is the ideal place to measure it precisely. Although the precision of present tests of the standard model requires a knowledge of M Z to only a few tens of MeV, a direct measurement of the mass ..
Study of Hadronic Decays of the Z Boson at LEP
No full textThis report summarizes four recent papers on the characteristics of the hadronic decays of the Z by the LEP collaborations ALEPH, DELPHI and OPAL
Review of Precision Determinations of the Accelerator Luminosity in LEP Experiments
No full textThe LEP collaborations ALEPH, DELPHI, L3 and OPAL were able to measure the accelerator luminosity with an experimental uncertainty smaller than 0.1%. Motivations, method, technological aspects and main difficulties of the measurements are reviewed
Combined Preliminary Results on the Mass and Width of the W Boson measured by the LEP Experiments
No full textElectroweak parameters of the Z° resonance and the standard model
Get PDFThe four LEP experiments have each performed precision measurements of Z ° parameters. A method is described for combin- ing the results of the four experiments, which takes into account the experimental and theoretical systematic errors and their correlations. We apply this method to the 1989 and 1990 LEP data, corresponding to approximately 650 000 Z ° decays into hadrons and charged leptons, to obtain precision values for the Z ° parameters. We use these results to test the standard model and to constrain its parameters.Facultad de Ciencias Exacta
Electroweak parameters of the Z° resonance and the standard model
Get PDFThe four LEP experiments have each performed precision measurements of Z ° parameters. A method is described for combin- ing the results of the four experiments, which takes into account the experimental and theoretical systematic errors and their correlations. We apply this method to the 1989 and 1990 LEP data, corresponding to approximately 650 000 Z ° decays into hadrons and charged leptons, to obtain precision values for the Z ° parameters. We use these results to test the standard model and to constrain its parameters.Facultad de Ciencias Exacta
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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