1,721,317 research outputs found
A search for flavor-changing neutral current interactions in leptonic final states using the CMS detector
No full textThe Large Hadron Collider (LHC) is the world’s largest particle accelerator. In 2012, the LHC announced that a new particle had been observed with data collected from its two major experiments, including the Compact Muon Solenoid (CMS). Since then, particle physicists have studied this new particle extensively and determined that it has the properties of the Higgs Boson. We are now in an era of particle physics where the Higgs boson can be used to probe theories of physics beyond the Standard Model (BSM). In this thesis, I am using it to search for flavor-changing neutral current (FCNC) interactions, where the Higgs Boson plays the role of the neutral mediator of a quark flavor-change. These processes are greatly suppressed in the Standard Model but could be enhanced by several theories beyond the SM. The Standard Model predicted cross section for these interactions is on the order of 10^(−15) fb, which is too rare to be observed with the LHC. This means that any observance of FCNC interactions would be evidence of BSM physics. The presented analysis sets upper limits on the coupling constant of the top quark, Higgs Boson, and either an up or a charm quark, using data collected at CMS during 2016-2018. In this thesis, I will present my search for FCNC in leptonic final states, which utilizes robust, data-driven background estimation methods and multivariate techniques to improve our results.2025-09-17T00:00:00
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Search for New Heavy Resonances Decaying To t+t^- Pairs at the LHC with Square Root S= 7 TEV (L = 5.0 FB^-1)
No full textThe Standard Model (SM) describes the known fundamental particles and their interactions due to the electromagnetic, weak, and strong forces through vector boson exchange. Although the SM has had major success in predicting a wealth of experimental measurements, astrophysical evidence for dark matter the observation of neutrino oscillations, and the matter-antimatter asymmetry in the universe indicate that the SM is not a complete theory. In addition to these experimental observations, problems stemming from the failure to incorporate the gravitational force and the quantum instability of the mass of the Higgs Boson have also contributed to the motivation to search for physics beyond the SM. Multiple theoretical scenarios, including those inspired by Grand Unified Theories (GUTs), models with extra spatial dimensions, and Supersymmetry (SUSY), have been proposed to address the shortcomings of the SM. In many of these models, the new symmetries that extend the SM gauge structure require the existence of new heavy neutral gauge bosons. Regardless of the exact nature or production mechanism of the hypothesized heavy bosons, they may be observed by studying dilepton final states at high energy colliders. As many models of physics beyond the SM predict enhanced couplings to third generation particles, searches for the new heavy bosons decaying into two �� -leptons are particularly well motivated. We present a direct search for high mass neutral resonances decaying into two opposite sign ��-leptons using data from proton-proton collisions at the LHC with center-of-mass energy square root of s = 7 TeV. The search has been conducted using data recorded by the Compact Muon Solenoid (CMS) experiment, corresponding to an integrated luminosity of 4.94 fb���1 and includes final states with leptonic and hadronic decays of the ��-lepton. The data has been found to be consistent with the background-only hypothesis within the sensitivity of the measurement. Using the Sequential Standard Model Z���-boson as a benchmark, we set a 95% confidence-level upper limit on the mass of Z���-bosons decaying to pairs of ��-leptons
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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