1,721,877 research outputs found
Avalanche in the Valley (Fermions, Anomaly and Unitarity in High-Energy Electroweak Interactions)
No full textProblems related to fermions, unitarity and chiral anomaly in high energy
electroweak interactions, are investigated. Particular attention is paid to the
correct functional integration over fermion fields in the background of
instanton-anti\-instanton type configurations. This leads to an expansion of
correlation functions in terms of a small parameter, , when the
instanton-antiinstanton separation () is large compared to their sizes
(). Applying such a method to widely discussed cases of fermion-number
violation in the electroweak theory, we conclude that there are no theoretical
basis for expecting anomalous cross sections to become observable at energies
in the TeV region
All order I.R. finite expansion for short distance behavior of massless theories perturbed by a relevant operator
No full text
FERMIONS IN THE INSTANTON ANTI-INSTANTON VALLEY AND HIGH-ENERGY ELECTROWEAK INTERACTIONS
No full textWe consider the behavior of fermions in the background of instanton-anti-instanton valley fields. Several different physics problems, from the high-energy electroweak interactions to the study of vacuum structure of QCD and of large orders of perturbation theory, are related to this problem. The spectrum of the Dirac operator in such a background is studied in detail. We present an approximation for the fermion correlation function when the instanton-anti-instanton separation (R) is large compared to their sizes (rho). The situation where the instanton-anti-instanton overlap and melt is studied through the behavior of the Chem-Simons number as a function of R/rho and x4. Applying our results to widely discussed cases of fermion-number violation in the electroweak theory, we conclude that there is no theoretical basis for expecting anomalous cross-sections to become observable at energies in the 10 TeV region
On the Short Distance Behavior of the Critical Ising Model Perturbed by a Magnetic Field
No full text
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
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