1,721,352 research outputs found
Measurements of the CP structure of Higgs-boson couplings with the ATLAS experiment
No full textWhile the Standard Model predicts that the Higgs boson is a CP-even scalar, CP-odd contributions to the Higgs boson interactions with fermions and vector bosons are presently not strongly constrained. A variety of Higgs boson production processes and decays can be used to study the CP nature of the Higgs boson interactions. This talk presents the most recent CP measurements by the ATLAS experiment, based on the full dataset collected in pp collisions at 13 TeV during Run 2 of the LHC
Measuring the speed of sound in air using a smartphone and a cardboard tube
No full textThis paper demonstrates a variation on the classic Kundt's tube experiment for measuring the speed of sound. The speed of sound in air is measured using a smartphone and a cardboard tube, making the experiment very economical in terms of equipment. The speed of sound in air is measured to within 3% of the theoretical prediction
Measurements of the CP Structure of Higgs Boson Couplings With the ATLAS Experiment
No full textThe Standard Model predicts a CP-even Higgs boson. Therefore, CP violation in the Higgs sector could be a possible probe for physics beyond the Standard Model. This work presents four recent searches for CP violation in Higgs boson interaction performed by the ATLAS collaboration at the Large Hadron Collider at CERN. These searches utilise the full Run 2 dataset and cover both bosonic and fermionic Higgs interactions. No significant deviations from Standard Model expectations are observed, but limits are placed on relevant parameters in Standard Model effective field theory and on the parameters of the general effective Yukawa interaction
Search for lepton flavour violating Higgs decays at 13 TeV
No full textMaster i FysikkMAMN-PHYSPHYS39
Searching for New Physics in Resonant and Non-Resonant Dilepton Final States With the ATLAS Detector at the LHC
No full textThe Standard Model, the mathematical description of the interactions of elementary particles, has proven to be a successful framework. Since its finalisation in the 1970s, no significant deviations have been measured from its predictions. However, some phenomena are not currently explained by the Standard Model: What is the nature of dark matter? Can a quantum theory of gravity be constructed? Numerous extensions to the Standard Model have been put forth over the years, trying to answer these, and other, questions about nature. Theoretical extensions of the Standard Model may yield different predictions about nature than the Standard Model itself. Physicists look for evidence of new physics by finding discrepancies from predictions, for example in particle collision experiments.
We search for discrepancies to the Standard Model predictions by analysing proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider, located at the CERN particle physics laboratory in Switzerland. Specifically, we select particle collision events for analysis where the final state of the collisions are two electrons or muons. We perform two separate searches for new physics on this dataset. The first is a search for so-called resonant phenomena, manifesting as localised deviations from the Standard Model prediction, in the reconstructed mass of the selected lepton pairs. The second search is for non-resonant phenomena, where the new physics is expected to appear as broad deviations to the Standard Model predictions in the high mass region of the data. In both searches, the Standard Model background prediction is estimated by fitting a functional form to the data.
No significant deviation from the background estimate is observed in either search. We set upper limits on the cross-section of a generic dilepton resonance and lower limits on the mass of a potential new heavy neutral boson. We also set lower limits on the so-called string scale parameter of the Arkani-Hamed, Dimopoulos, and Dvali model of large extra dimensions. This model may explain the discrepancy in strength between the particle interactions of the Standard Model, and gravity
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
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
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