1,296 research outputs found

    Model calculations of the Sivers function satisfying the Burkardt Sum Rule

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    It is shown that, at variance with previous analyses, the MIT bag model can explain the available data of the Sivers function and satisfies the Burkardt Sum Rule to a few percent accuracy. The agreement is similar to the one recently found in the constituent quark model. Therefore, these two model calculations of the Sivers function are in agreement with the present experimental and theoretical wisdom.Comment: 9 pages, 4 figures; one figure added; references added; slightly revised version accepted for publication in Phys. Rev.

    A quark model analysis of the Sivers function

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    We develop a formalism to evaluate the Sivers function. The approach is well suited for calculations which use constituent quark models to describe the structure of the nucleon. A non-relativistic reduction of the scheme is performed and applied to the Isgur-Karl model of hadron structure. The results obtained are consistent with a sizable Sivers effect and the signs for the u and d flavor contributions turn out to be opposite. This pattern is in agreement with the one found analyzing, in the same model, the impact parameter dependent generalized parton distributions. The Burkardt Sum Rule turns out to be fulfilled to a large extent. We estimate the QCD evolution of our results from the momentum scale of the model to the experimental one and obtain reasonable agreement with the available data.Comment: 31 pages, 4 figures. Extended version, discussion of the Burkardt Sum Rule added, references added, minor changes in the numerical results, same interpretation. Final version accepted for publication in Phys. Rev.

    Nuclear and partonic dynamics in the EMC effect

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    It has been recently confirmed that the magnitude of the EMC effect measured in electron deep inelastic scattering is linearly related to the Short Range Correlation scaling factor obtained from electron inclusive scattering. By using a xx-rescaling approach we are able to understand the interplay between the quark-gluon and hadronic degrees of freedom in the discussion of the EMC effect.Comment: 5 pages, 6 figures, 2 table. We have incorporated SLAC data and redone the calculation with the newest ROOT 5.3

    The suburban question: grassroots politics and place making in Spanish suburbs

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    Manuel Castells spoke of the urban as a unit of collective consumption, yet much of the politics of collective consumption he documented was evident in the suburbs. The tendency for suburbs of most complexions to lack services and amenities has been and continues to be a focus of politics in Europe. In Spain, as elsewhere in Europe, a grassroots politics surrounding the making good of these deficits in basic services and amenities has broadened and formalised somewhat to become part of a competitive local representative politics concerned with shaping a sense of place. Here we consider this legacy of grassroots politics as it has played out more recently in a politics of place making in Getafe and Badalona in metropolitan Madrid and Barcelona, respectively. In conclusion, we suggest that this enduring suburban question—of making the suburban urban—places them at the centre of contemporary metropolitan governance and politics. However, it also raises further issues for study—notably, the scalar politics in which suburban place making is empowered or constrained, the role of political parties and individual politicians on the place-making process, and the point at which grassroots politics of collective consumption becomes urban entrepreneurialism

    eta - eta' - glueball mixing

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    We have revisited glueball mixing with the pseudoscalar mesons in the MIT bag model scheme. The calculation has been performed in the spherical cavity approximation to the bag using two different fermion propagators, the cavity and the free propagators. We obtain a very small probability of mixing for the eta at the level of $0.04-0.1% and a bigger for the eta' at the level of 4-12%. Our results differ from previous calculations in the same scheme but seem to agree with the experimental analysis. We discuss the origin of our difference which stems from the treatment of our time integrations.Comment: 21 pages, 7 figure

    Book Review: Telepractice in Audiology

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    This article presents a review of the book Telepractice in Audiology, authored by Emma Rushbrooke MPhil(AUD), BA, DipAud., MAudSA., LSLS. Cert. AVT, RNC, and K. Todd Houston, PhD, CCC-SLP, LSLS Cert. AVT, and 13 contributing authors.  This is the first book entirely devoted to tele-audiology. It provides practical information for working with clients across the lifespan and for multiple practice settings. Reviewer Dr. Barbara Vento endorses this work as a comprehensive resource on the topic of teleaudiology for both students and aspiring teleaudiologists.

    Medium Effects in DIS from Polarized Nuclear Targets

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    The behavior of the nucleon structure functions in lepton nuclei deep inelastic scattering, both polarized and unpolarized, due to nuclear structure effects is reanalyzed. The study is performed in two schemes: an x-rescaling approach, and one in which there is an increase of sea quark components in the in medium nucleon, related to the low energy N-N interaction. In view of a recent interesting experimental proposal to study the behavior of the proton spin structure functions in nuclei we proceed to compare these approaches in an effort to enlighten the possible phenomenological interest of such difficult experiment.Comment: 11 pages and 5 figure
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