1,721,573 research outputs found
Optical survey of a lead scintillating fiber calorimeter by digital imaging techniques
No full textAn application of digital imaging techniques to the optical inspection of a lead scintillating fiber calorimeter prototype is described. The method provides accurate measurements of fibers position and light transmission properties
Measurement of the D0−D¯0{D^0} - {mathop Dlimits^ ^0} mixing at CDF
No full textWe report on the observation of D0−D¯0{D^0} - {mathop Dlimits^ ^0} oscillations by measuring the time-dependent ratio of yields for the rare decay D0 → K+π− to the favored decay D0 → K−π+ at the Collider Detector at Fermilab (CDF). Using 9.6 fb−1 of integrated luminosity of √s = 1.96 TeV pp¯ collisions recorded in the full CDF Run II, the signals of 7.6×106 D0 → K−π+ and 33×103 D0 → K+π− decays are reconstructed in D*-tagged events, with proper decay times between 0.75 and 10 mean D0 lifetimes. We measure the mixing parameters x′2 = (0.08 ± 0.18) × 10−3, y′ = (4.3 ± 4.3) × 10−3, and RD = (3.51 ± 0.35) × 10−3. Our results are consistent with standard model expectations and similar results from proton-proton collisions and exclude the no-mixing hypothesis with a significance equivalent to 6.1 standard deviations
Observation of charm mixing at CDF
Get PDFWe report on the observation of D0-D̄0 oscillations by measuring the time-dependent ratio of yields for the rare decay D0 → K+π- to the favored decay D 0→K-π+ at the Collider Detector at Fermilab (CDF). Using 9.6 fb-1of integrated luminosity of√s = 1.96 TeV pp̄ collisions recorded in the full CDF Run II, the signals of 7.6×106 D0 →K-π+ and 33×103 D0 → K+π- decays are reconstructed in D*-tagged events, with proper decay times between 0.75 and 10 mean D0 lifetimes. We measure the mixing parameters x′2= (0.08±0.18)×10-3, y′ = (4.3±4.3)×10-3, and RD = (3.51±0.35)×10-3. Our results are consistent with standard model expectations and similar results from proton-proton collisions and exclude the no-mixing hypothesis with a significance equivalent to 6.1 standard deviations
The CALET mission on the International Space Station
Get PDFThe CALorimetric Electron Telescope (CALET) is an astroparticle physics experiment currently under preparation to be installed on the International Space Station. Its main scientific goal is to search for possible clues of the presence of astrophysical sources of high-energy electrons nearby the Earth or signatures of dark matter, by measuring accurately the electron spectrum up to several TeV. CALET will also investigate the mechanism of cosmic-ray (CR) acceleration and propagation in the Galaxy, by performing direct measurements of the energy spectra and elemental composition of CR nuclei from H to Fe up to several hundreds of TeV, and the abundance of trans-iron elements at few GeV/amu up to about Z=40. The instrument consists of two layers of segmented plastic scintillators to identify the particle charge, a thin tungsten- scintillating fiber calorimeter providing accurate particle tracking, and a thick crystal calorimeter to measure the energy of CRs with excellent resolution and electron/hadron separation up to the multi-TeV scale. In this paper, we will review the status of the CALET mission, the instrument configuration and its performance, and the expected measurements of the different components of the cosmic radiation in 5 years of observations
Particle tracking in the CALET experiment
Get PDFThe Calorimetric Electron Telescope (CALET) is a space mission installed on the Exposed Fa- cility of the Japanese Experiment Module (JEM-EF) of the International Space Station (ISS) in August 2015 and collecting data since October 2015. In addition to high precision measure- ments of the electron spectrum up to TeV scale, CALET will also investigate the mechanism of cosmic-ray (CR) acceleration and propagation in the Galaxy, by performing direct measurements of the energy spectra and elemental composition of CR nuclei from H to Fe, and the abundance of trans-iron elements up to about Z=40. The instrument consists of two layers of segmented plas- tic scintillators to identify the particle charge, a thin (3 radiation lengths) tungsten-scintillating fiber calorimeter providing accurate particle tracking, and a thick (27 radiation lengths) calorime- ter made of lead-tungstate crystal logs. In this paper we will describe an original reconstruction method of the primary particle direction based on a combinatorial Kalman filter algorithm. This method exploits the fine granularity and imaging capability of the IMC and provides robust track finding and fitting, allowing to identify the incident CR track in a large amount of shower par- ticle tracks backscattered from the calorimeter. The track fitting algorithm has been extensively validated and tuned with simulated data. Its performance (angular resolution, impact point res- olution, tracking efficiency) for electrons and nuclei will be discussed and comparisons between flight data and simulations will be shown
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
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