1,720,964 research outputs found
The Higgs boson’s lifetime measurement via off-shell decays to W-bosons
No full textThe discovery of the Higgs boson just over 10 years ago motivated many new questions as to the precise nature of this elusive particle. One such question pertains to the lifetime of the Higgs boson, which is a particularly interesting quantity as it holds information on the particle content in our universe. Measuring a deviation from the standard model might indicate that there exist different types of particles in our universe, beyond the ones we currently know to exist through experimental evidence. Measuring the lifetime of the Higgs boson is however complicated by the fact that the Standard Model predicts it to be extremely short, so short that it was long thought to not be within experimental reach of the particle detectors at the LHC in CERN. However, using a technique which relies on its off-shell decays the lifetime of the Higgs boson can experimentally be determined with great precision. In this presentation I will show this technique applied to Higgs bosons when they decay via two W-bosons. I will introduce how this technique is applied in practice to experimental data collected by the ATLAS detector at CERN, leading to the most sensitive measurement of the Higgs boson lifetime in the WW-channel to date. The results reveal that we can indeed experimentally constrain the Higgs width to within a couple Mega-electronVolt (MeV) in this channel, reaching a precision that is of the same order of magnitude as the width itself. The results are moreover compatible with predictions from the standard model, proving once again that the standard model has excellent predictive power within the current range of energies explored at the LHC
Analysis strategy of corrected B mass components in LHCb run II dataset
No full textThe development of an analysis framework for the various components that make up B meson mass after DaVinci processing is a crucial step towards the determination of the amount of CP violation in B0 - B¯0 mixing. Previously, a model for this was made for the data collected in LHC Run I. In the present research, this analysis model was rebuilt from scratch and expanded upon so as to form one complete software that was capable of conducting the full analysis on the Run II 2016 dataset. Finally, the new framework was also tested on the Run II 2015 dataset so as to give an overview of the consistency compared to the previous work. The addition to the analysis was successful in reducing the number of preassumed parameters
Lower limits on the Higgs boson lifetime via off-shell decays into final states with the ATLAS detector.
No full textThis article presents an analysis of the off-shell Higgs boson production rate in the decay mode and interprets the results in terms of the Higgs boson’s lifetime---or equivalently, its total width---focusing on final states in which both bosons decay leptonically. The study uses proton–proton collision data corresponding to an integrated luminosity of 140 , recorded at a center-of-mass energy of 13 TeV by the ATLAS experiment at the LHC. The observations are consistent with predictions from the Standard Model. A 95% CL upper limit is placed on the off-shell Higgs production rate at 3.4 times the Standard Model expectation, with an expected limit of 4.4. By combining these findings with measurements of the on-shell Higgs production rate in identical final states, a 95% CL lower bound on the Higgs boson lifetime is set at 5.0 s, with an expected lower bound of 3.8 s
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
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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