1,721,001 research outputs found
A search for third-generation leptoquarks in the non-resonant production with the ATLAS experiment and development of the Level-0 muon trigger for the High Luminosity LHC
No full textRecent observations performed by several high-energy physics experiments have shown anomalies in b-hadron decays, which could be explained by assuming the existence of a particle, the leptoquark, coupled both to leptons and quarks. Such measurements also suggest a preferential coupling to third-generation fermions. In this thesis, a search for third-generation leptoquarks is presented, considering the non-resonant leptoquark production. The non-resonant production is expected to yield high sensitivity from the large interference term between the Standard Model Drell-Yan process and the leptoquark t-channel exchange. The leptoquark search uses the 140 fb−1 of pp collision data collected by the ATLAS detector during the LHC Run 2 and considers di-lepton final state events, with at least one hadronically decaying tau-lepton. Deviations from the Standard Model predictions are looked for in the visible invariant mass spectrum of the di-lepton system, binned in b-jet multiplicity. In the absence of a significant deviation, exclusion limits are determined on the leptoquark coupling for different leptoquark mass values.
This thesis also presents a contribution to the upgrade of the ATLAS Muon Spectrometer in preparation for the High-Luminosity LHC. In order to cope with the much harsher conditions of the high-luminosity phase of the LHC, the entire trigger and readout electronics of the Resistive Plate Chamber detectors in the barrel region of the Muon Spectrometer will be replaced and novel FPGA-based boards will be installed. On-detector Data Collector and Transmitter boards will collect the front-end data and transmit them to off-detector Sector Logic boards, which will execute the Level-0 Muon trigger algorithm and the readout logic. In this thesis, the development of the firmwares that will be implemented in the FPGAs of the Data Collector and Transmitter boards and of the barrel Sector Logic boards is presented
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
Estimation of backgrounds from jets misidentified as tau leptons using the Universal Fake Factor method with the ATLAS detector
No full textPhysical processes with one or more τ-lepton in the final state play an important role in several analyses of the ATLAS experiment physics program. The usage of hadronic channels, in which τ-leptons decay into one or more pions, enables to exploit the large statistics associated with hadronic τ-lepton decays, but also requires a precise estimate of a sizable background of hadronic jets mis-reconstructed as fake τ-leptons. This poster will present a new technique developed by the ATLAS Collaboration to estimate the fake τ-lepton background from data - the Universal Fake Factor method. This technique improves on previous methodologies as it enables a more solid validation of the estimated background. Details on how to implement this methodology will be given as well as on its validation with single and di-τ final states. Information on ATLAS physics analyses that successfully exploited this technique will also be given
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
A search for third-generation leptoquarks in the non-resonant production with the ATLAS experiment and development of the Level-0 muon trigger for the High Luminosity LHC
No full textRecent observations performed by several high-energy physics experiments have shown anomalies in -hadron decays, which could be explained by assuming the existence of a particle, the leptoquark, coupled both to leptons and quarks. Such measurements also suggest a preferential coupling to third-generation fermions. In this thesis, a search for third-generation leptoquarks is presented, considering the non-resonant leptoquark production. The non-resonant production is expected to yield high sensitivity from the large interference term between the Standard Model Drell-Yan process and the leptoquark t-channel exchange. The leptoquark search uses the 140 fb of collision data collected by the ATLAS detector during the LHC Run 2 and considers di-lepton final state events, with at least one hadronically decaying tau-lepton. Deviations from the Standard Model predictions are looked for in the visible invariant mass spectrum of the di-lepton system, binned in b-jet multiplicity. In the absence of a significant deviation, exclusion limits are determined on the leptoquark coupling for different leptoquark mass values. This thesis also presents a contribution to the upgrade of the ATLAS Muon Spectrometer in preparation for the High-Luminosity LHC. In order to cope with the much harsher conditions of the high-luminosity phase of the LHC, the entire trigger and readout electronics of the Resistive Plate Chamber detectors in the barrel region of the Muon Spectrometer will be replaced and novel FPGA-based boards will be installed. On-detector Data Collector and Transmitter boards will collect the front-end data and transmit them to off-detector Sector Logic boards, which will execute the Level-0 Muon trigger algorithm and the readout logic. In this thesis, the development of the firmwares that will be implemented in the FPGAs of the Data Collector and Transmitter boards and of the barrel Sector Logic boards is presented
The ATLAS Muon Trigger System for the High Luminosity LHC
No full textTo preserve the acceptance of critical signatures for physics in the increased particle rates, integrated radiation, and pile-up conditions of the High Luminosity the HL-LHC runs, the Trigger and Readout System of the ATLAS Muon Spectrometer must maintain low-momentum trigger thresholds in an acceptable trigger rate. This leads to an increase of the trigger rate and latency to 1MHz and 10μs, respectively, so that more complex trigger algorithms than in the present system can be implemented. That trigger scheme imposes the replacement of the current readout and trigger electronics, which accommodate a maximum rate of 100 kHz with a maximum latency of up to 3 μs. This paper presents the new muon hardware trigger architecture that exploits the Muon Spectrometer’s upgraded trigger and readout electronics, focusing on the new data collection and transmission electronics (DCT) of the Resistive Plate Chambers (RPC) trigger detector technology. The DCT boards implement the LPGBT optical link to handle data bandwidth up to 10.24 Gb/s. Due to the importance of the DCT system, the complexity of the signals it handles, and the large number of boards required (1570 DCTs), an automated test station will be developed to evaluate the performance of all its functionalities. Presented are the architecture and measurement results of a test bench developed to evaluate the DCT's optical link LpGBT by implementing its backend counterpart (lpGBTFPGA core). Since the DCT prototype is under irradiation tests, for the assessment of the lpGBT-FPGA a methodology has been implemented by using development boards and modifying the alternative of the LPGBT ASIC (lpGBT-Emulator). The successful operation of the above testing setup renders feasible indispensable implementations towards the complete validation of the functionalities of the DCT (or of any board that implements the LPGBT)
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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