1,721,234 research outputs found
Differentiating Top-Quark - Photon Coupling: Inclusive and Differential Cross-Section Measurements of Top-Quark Pair Production in Association with a Photon in the Single Lepton Channel in pp Collisions Data at 8 TeV with the ATLAS Experiment
No full textMessungen der inklusiven und differentiellen Wirkungsquerschnitte der Entstehung des Top-Quark-Paares unter Photonbeteiligung im Einzel-Leptonen-Kanal bei einer Schwerpunktsenergie von √s 8TeV mit Proton-Proton Kollisions-Daten aufgezeichnet vom ATLAS Detektor
No full textThis thesis presents measurements of inclusive and differential production cross sections of top- anti-top-quark pairs in association with an additional prompt photon ttγ in the single lepton final state at the LHC analysing data recorded by the ATLAS detector. The data analysed corresponds to 20.2 fb-1 of integrated luminosity recorded during 2012 at a center-of-mass energy of √s = 8 TeV. The cross.section is measured with a template fit method. Background processes are estimated with data driven and Monte Carlo based methods. The differential cross section is measured as a function of transverse momentum and pseudo-rapidity of the photon. A total of 1256 and 1816 candidate ttγ events are observed in the electron and muon channel, respectively. Both inclusive and differential measurements are performed in a fiducial phase space within the detector acceptance. The differential measurements are performed as a function of transverse momentum and pseudo-rapidity of the photon. The inclusive ttγ production cross section times the branching ratio (BR) is measured to be 71.4 ± 13.0 fb in the electron channel. The measured cross section in the muon channel reads 70.0 ± 9.8 fb. The results are in agreement within the uncertainties with the corresponding Standard model predictions at next-to-leading order.Die Messungen der inklusiven und differentiellen Wirkungsquerschnitte der Entstehung eines Top-Quark-Paares unter Abstrahlung eines zusätzlichen Photons ttγ im Einzel-Leptonen-Kanal wird vorgestellt. Die Messungen wurden mit Hilfe einer Template-Fit-Methode unter Verwendung eines Datensatzes mit einer integrierten Luminosität von 20.2 fb-1 von Proton-Proton Kollisions-Daten aufgezeichnet vom ATLAS Detektor durchgeführt. Die Messung der differentiellen Wirkungsquerschnitte wurde als Funktion von transversalem Impuls und Pseudo-Rapididät des Photons durchgeführt. Verschiedene Untergrund- Beiträge wurden mit datengestützten Verfahren oder mit der Hilfe von Monte-Carlo-Daten untersucht. Es wurden insgesamt 1256 ttγ-Kandidaten im Elektron- und 1816 Kandidaten im Myon-Kanal beobachtet. Die Messung des inklusiven Wirkungsquerschnitts liefert ein Ergebnis von 71.4 ± 13.0 fb für das Elektron-Kanal und 70.0 ± 9.8 fb für das Myon-Kanal. Die Messungen sind in guter Übereinstimmung mit theoretischen Vorhersagen im Rahmen der experimentellen und theoretischen Unsicherheiten
Differentiating Top-Quark - Photon Coupling: Inclusive and Differential Cross-Section Measurements of Top-Quark Pair Production in Association with a Photon in the Single Lepton Channel in pp Collisions Data at = 8TeV with the ATLAS Experiment
No full textThis thesis presents measurements of inclusive and differential production cross sections of top- anti-top-quark pairs in association with an additional prompt photon () in the single lepton final state at the LHC analysing data recorded by the ATLAS detector. The data analysed corresponds to 20.2 fb of integrated luminosity recorded during 2012 at a center-of-mass energy of = 8 TeV. The cross.section is measured with a template fit method. Background processes are estimated with data driven and Monte Carlo based methods. The differential cross section is measured as a function of transverse momentum and pseudo-rapidity of the photon. A total of 1256 and 1816 candidate events are observed in the electron and muon channel, respectively. Both inclusive and differential measurements are performed in a fiducial phase space within the detector acceptance. The differential measurements are performed as a function of transverse momentum and pseudo-rapidity of the photon. The inclusive production cross section times the branching ratio (BR) is measured to be BR = 71.4 13.0 fb in the electron channel. The measured cross section in the muon channel reads BR = 70.0 9.8 fb. The results are in agreement within the uncertainties with the corresponding standard model predictions at next-to-leading order
Top quark production measurements using the ATLAS detector at the LHC
No full textA selection from the inclusive top-quark pair production and single top-quark production cross-section measurements in proton-proton collisions with the ATLAS detector at the Large Hadron Collider is presented, with data collected in 2012 and early 2015 at centre-of-mass energies of 8 TeV and 13 TeV, respectively
Top quark production measurements using the ATLAS detector at the LHC
Get PDFA selection from the inclusive top-quark pair production and single top-quark production cross-section measurements in proton-proton collisions with the ATLAS detector at the Large Hadron Collider is presented, with data collected in 2012 and early 2015 at centre-of-mass energies of 8 TeV and 13 TeV, respectively
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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