1,721,341 research outputs found
Probing charm-quark fragmentation by correlation and jet measurements in pp collisions with ALICE
No full textHeavy-flavor measurements in ultrarelativistic hadronic collisions hold significance in validating perturbative QCD. The recent observation of an enhanced baryon-tomeson ratio at the low transverse momenta in hadronic collisions compared to e+e − and e −p collisions has disproven the universality of fragmentation fractions across colliding systems. Discrepancies between experimental measurements in hadronic collisions and models that rely on fragmentation functions constrained to e+e − and e−p data have also been obsereved. Charm-tagged jets measurements and azimuthal correlations between charmed hadrons and other charged particles offer supplementary insights into charm fragmentation mechanisms
Exploring charm-quark fragmentation with correlation and jet measurements by ALICE
No full textFragmentation functions, one of the key components of the factorisation theorem used for computing cross sections for heavy-flavour hadron production, are typically constrained in and collisions due to their non-perturbative nature.However, recent measurements of charm-hadron spectra and ratios at the LHC have questioned the universality of fragmentation functions across leptonic and hadronic collision systems.This contribution presents measurements of heavy-flavour tagged jets and correlation measurements involving heavy-flavour hadrons. These measurements provide complementary, and more differential, insights on heavy-quark production, fragmentation and hadronization with respect to more inclusive observables.The studies presented include measurements of the -differential cross section of D-tagged charm-jets and the longitudinal jet momentum fraction carried by D mesons and baryons reconstructed inside jets in pp collisions. The measurements of azimuthal correlations between D mesons and charged particles in pp collisions are presented, to provide a quantitative access to the angular profile, transverse-momentum and multiplicity distributions of the jets produced by the heavy-quark fragmentation. To gain a deeper understanding on possible differences in charm-quark hadronization into mesons or baryons, the comparison of azimuthal correlations between baryons and D mesons with charged particles in pp collisions is also discussed
Measurement of Heavy-Flavour Correlations and Jets with ALICE at the LHC
No full textIn this article, we report the latest results on heavy-flavour correlations and jets measured with the ALICE detector in pp, p–Pb and Pb–Pb collisions from the LHC Run 2. The results of azimuthal correlations between D mesons and charged particles in pp collisions at = 7 TeV and 13 TeV and in p–Pb collisions at = 5.02 TeV are presented. The centrality-dependent study on azimuthal correlations between electrons from open heavy-flavour hadron decays and charged particles in Pb–Pb collisions at = 5.02 TeV are performed. In addition, measurements of D-meson tagged jet production in pp collisions at TeV and in p–Pb collisions at = 5.02 TeV are presented
Azimuthal correlations of D mesons with charged particles in pp collisions at = 13 TeV with the ALICE experiment at the LHC
No full textThe study of azimuthal correlations of heavy-flavour hadrons with charged particles is an important tool to characterize charm fragmentation processes. It gives insight into the modi- fication of charm-jet properties in nucleus-nucleus collisions and the mechanisms through which heavy quarks in-medium energy-loss takes place. Studies in pp collisions, besides constituting the necessary baseline for nucleus-nucleus measurements, are important for testing pQCD-inspired Monte Carlo generators. In this proceeding, the latest heavy-flavour correlation results at mid- rapidity with the ALICE detector in pp collisions at = 13 TeV are reported. The results are compared with pp = 7 TeV and p-Pb = 5.02 TeV data. The yield of charged particles in the near-side correlation peak and the peak width measured in different systems are compatible, within the uncertainties, and described by Monte Carlo simulations
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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