269 research outputs found

    Estimating sigma-meson couplings from D \to 3\pi decays

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    Using recent experimental evidence from E791 on the sigma meson in D \to 3\pi decays, we study the relevant couplings in D \to \sigma \pi and \sigma \to \pi\ pi within the accepted theoretical framework for non leptonic D decays. We also review the linear sigma model, finding that it gives a description which is consistent with the experimental data.Comment: 6 pages, no figures. Final version accepted for publication as a Brief Report in Physical Review

    On the equivalence between Implicit Regularization and Constrained Differential Renormalization

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    Constrained Differential Renormalization (CDR) and the constrained version of Implicit Regularization (IR) are two regularization independent techniques that do not rely on dimensional continuation of the space-time. These two methods which have rather distinct basis have been successfully applied to several calculations which show that they can be trusted as practical, symmetry invariant frameworks (gauge and supersymmetry included) in perturbative computations even beyond one-loop order. In this paper, we show the equivalence between these two methods at one-loop order. We show that the configuration space rules of CDR can be mapped into the momentum space procedures of Implicit Regularization, the major principle behind this equivalence being the extension of the properties of regular distributions to the regularized ones.Comment: 16 page

    Neutron charge form factor at large q2q^2

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    The neutron charge form factor GEn(q)G_{En}(q) is determined from an analysis of the deuteron quadrupole form factor FC2F_{C2} data. Recent calculations, based on a variety of different model interactions and currents, indicate that the contributions associated with the uncertain two-body operators of shorter range are relatively small for FC2F_{C2}, even at large momentum transfer qq. Hence, GEn(q)G_{En}(q) can be extracted from FC2F_{C2} at large q2q^2 without undue systematic uncertainties from theory.Comment: 8 pages, 3 figure

    Elastic electron deuteron scattering with consistent meson exchange and relativistic contributions of leading order

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    The influence of relativistic contributions to elastic electron deuteron scattering is studied systematically at low and intermediate momentum transfers (Q230Q^2\leq 30 fm2^{-2}). In a (p/M)(p/M)-expansion, all leading order relativistic π\pi-exchange contributions consistent with the Bonn OBEPQ models are included. In addition, static heavy meson exchange currents including boost terms and lowest order ρπγ\rho\pi\gamma-currents are considered. Sizeable effects from the various relativistic two-body contributions, mainly from π\pi-exchange, have been found in form factors, structure functions and the tensor polarization T20T_{20}. Furthermore, static properties, viz. magnetic dipole and charge quadrupole moments and the mean square charge radius are evaluated.Comment: 15 pages Latex including 5 figures, final version accepted for publication in Phys.Rev.C Details of changes: (i) The notation of the curves in Figs. 1 and 2 have been clarified with respect to left and right panels. (ii) In Figs. 3 and 4 an experimental point for T_20 has been added and a corresponding reference [48] (iii) At the end of the text we have added a paragraph concerning the quality of the Bonn OBEPQ potential

    Centrality Dependence of Charged Particle Multiplicity at Mid-Rapidity in Au+Au Collisions at sqrt(s_NN) = 130 GeV

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    We present a measurement of the pseudorapidity density of primary charged particles near mid-rapidity in Au+Au collisions at sqrt(s_NN) = 130 GeV as a function of the number of participating nucleons. These results are compared to models in an attempt to discriminate between competing scenarios of particle production in heavy ion collisions.Comment: 5 pages, 4 figures, revtex (submitted to Phys. Rev. Letters

    Limiting fragmentation in hadron-hadron collisions at high energies

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    Limiting fragmentation in proton-proton, deuteron-nucleus and nucleus-nucleus collisions is analyzed in the framework of the Balitsky-Kovchegov equation in high energy QCD. Good agreement with experimental data is obtained for a wide range of energies. Further detailed tests of limiting fragmentation at RHIC and the LHC will provide insight into the evolution equations for high energy QCD.Comment: 28 pages, 10 figures (2 new figures, text slightly expanded, and some additional references

    The necessity of historical inquiry in educational research: the case of Religious Education

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    publication-status: PublishedThis is an Author's Original Manuscript of an article whose final and definitive form, the Version of Record, has been published in the British Journal of Religious Education, July 2010. Available online at: http://www.tandfonline.com/ or DOI: 10.1080/01416200.2010.498612This article explores the mixed fortunes of historical inquiry as a method in educational studies and exposes evidence for the neglect of this method in religious education research in particular. It argues that historical inquiry, as a counterpart to other research methods, can add depth and range to our understanding of education, including religious education, and can illuminate important longer‐term, broader and philosophical issues. The article also argues that many historical voices have remained silent in the existing historiography of religious education because such historiography is too generalised and too biased towards the development of national policy and curriculum and pedagogical theory. To address this limitation in educational research, this article promotes rigorous historical studies that are more substantially grounded in the appropriate historiographical literature and utilise a wide range of original primary sources. Finally, the article explores a specific example of the way in which a historical approach may be fruitfully applied to a particular contemporary debate concerning the nature and purpose of religious education

    Oh Comrade, What Times those Were! History, Capital Punishment and the Urban Square.

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    From the perspective of traditional Western histories of the urban realm, public squares have been seen to represent a privileged site of urban containment expressive of a community's highest values of individual freedom, social inclusion and cultural refinement. But such views can be misleading. For what is omitted from the scope of these conventional historical visions and their ideal and conforming subjects of public spatial discourse, is an entire array of other and darker narratives that equally speak of personal choice, collective participation and cultural value. Capital punishment reflects such an example, a practice that once comprised an integral part of the political, social and cultural landscape of a Western city's squares and streets. Drawing from Michel Foucault's Discipline and Punish and its implications on how we might begin to re-read the history of the urban square, the following seeks to explore those practices and modes of rationality that underpinned the once public spectacle of executions and torture as a vital condition of urban life. In particular, this discussion will question the assumptions of an historical tradition that continues to reduce our understanding of the city and its open spaces of public appearance and action to an idealistic and illusory reality of the urban realm and its narrow framing of collective conduct, necessity and significance

    Avaliação das propriedades físicas e mecânicas de blocos de solo-cimento formulados com coprodutos siderúrgicos

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    RESUMO Este trabalho tem por objetivo caracterizar o desempenho de resistência mecânica e absorção de água de blocos solo-cimento para alvenaria, após 28 dias de cura, com a incorporação limite dos seguintes coprodutos siderúrgicos em substituição parcial ao solo: adições de até 20 % em massa do pó de balão coletado em alto-forno, até 10 % de poeiras de despoeiramento de aciaria elétrica, e até 20 % de escória granulada de forno elétrico a arco. As formulações propostas incluem adições simultâneas de pós obtidos do descarte da produção de blocos solo-cimento, onde a substituição parcial ao solo foi de até 20 % em massa. Os resultados obtidos sugerem a potencialidade de uso dos resíduos siderúrgicos em blocos intertravados de solo-cimento para alvenaria sustentável, como alternativa de aplicação para esses resíduos. Verificou-se a possibilidade de bons resultados confrontando os valores exigidos por norma (absorção de água < 20% e resistência mecânica > 2,0 MPa) com destaque quando se utilizou 20% pó de balão juntamente com 10% de reuso do bloco solo-cimento; 10% de escória de aciaria ou 20% de escória de aciaria juntamente com 10% de reuso do bloco solo-cimento; e 2,5% de pó de despoeiramento juntamente com 20% de reuso do bloco solo-cimento

    A gradient approach to localization of deformation. I. Hyperelastic materials

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    By utilizing methods recently developed in the theory of fluid interfaces, we provide a new framework for considering the localization of deformation and illustrate it for the case of hyperelastic materials. The approach overcomes one of the major shortcomings in constitutive equations for solids admitting localization of deformation at finite strains, i.e. their inability to provide physically acceptable solutions to boundary value problems in the post-localization range due to loss of ellipticity of the governing equations. Specifically, strain-induced localized deformation patterns are accounted for by adding a second deformation gradient-dependent term to the expression for the strain energy density. The modified strain energy function leads to equilibrium equations which remain always elliptic. Explicit solutions of these equations can be found for certain classes of deformations. They suggest not only the direction but also the width of the deformation bands providing for the first time a predictive unifying method for the study of pre- and post-localization behavior. The results derived here are a three-dimensional extension of certain one-dimensional findings reported earlier by the second author for the problem of simple shear.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42674/1/10659_2004_Article_BF00040814.pd
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