1,721,002 research outputs found
Phonon Excitation in Cubic Crystal Targets via Dark Matter Scattering
Get PDFThe scattering of dark matter (DM) particles to excite collective vibrational modes knownas phonons in crystal targets is a motivated method of observing DM with masses mχ < 1
MeV. This is due to the matching between the typical energy and momentum imparted into
the target and those of the phonons. For heavier dark matter particles with masses mχ ≳ 1
GeV, the scattering is instead point-like off of the individual nuclei in the crystal, rather than
collective scattering from many atoms. While the single phonon and nuclear recoil responses are
understood, the transition between the two is not. An understanding of this intermediate regime
requires a consideration of multiphonon processes, in particular as higher-order corrections that
increasingly contribute to the total scattering rate as the typical energy depositions increase. We
utilize several simplifying approximations to arrive at analytic descriptions for multiphonon
excitation, allowing us to fully characterize the crystal’s phonon response across the relevant
mass spectrum for incident DM. Our results allow us to identify the dominant signals to look
for in experimental DM searches with cubic crystal targets as a function of the detector energy
thresholds
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An introduction to quantum computing for high energy physics
Get PDFApplications of quantum computing to high energy physics (HEP) is a relatively new field of research. As such, the relevant literature is not well organized in one place and a clear road-map for people approaching the field is not currently available. Addressing this issue was the main motivation for this article, which is intended a pedagogical introduction to the field and specifically to our research direction, i.e. application of quantum computing to parton shower event generators, with the hope of more people becoming interested in exploring this path. Our paper on the subject, “A quantum algorithm for high energy physics simulations” [8], is the subject of chapter 4. I hope this article can provide a direct path for people familiar with quantum mechanics and quantum field theory to start reading papers or conducting research in this area of quantum computing applications in HEP. In this regard, the quantum algorithm we present in Chapter 4, can serve as an example of development of a novel efficient quantum algorithm to solve a problem in a particle physics model
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Dark Matter Direct Detection via Multiphonon Excitations in Crystal Targets
Get PDFIn dark matter direct detection experiments, the free nuclear recoil description breaks down as the de Broglie wavelength of dark matter approaches the typical atomic spacing of the target material. In this work, we investigate the particular case of scattering off of crystal targets, whose collective excitations are well understood as phonons. As experimental energy thresholds decrease, it becomes increasingly important to understand the response of targets to energy depositions below the nuclear recoil scale. For dark matter masses lighter than 1 MeV, the scattering rate is dominated by single phonons, while at masses larger than 100 MeV, we expect the scattering to approach the free nuclear recoil result. Starting from the phonon formalism in the harmonic crystal approximation, we perform the first calculations of scattering rates in the intermediate 1-100 MeV mass regime where multiphonon process dominate and demonstrate how the multiphonon response smoothly approaches free nuclear recoil. We then drop the harmonic approximation and calculate possible corrections to the scattering rates due to crystal anharmonicity. We find these anharmonic corrections to be large at small dark matter masses ∼ MeV and large experimental thresholds ∼ 100 MeV, but approach the harmonic result as the DM mass increases
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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