1,332 research outputs found
Model calculations of the Sivers function satisfying the Burkardt Sum Rule
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
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
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 -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
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
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
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. Â 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
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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