13,000 research outputs found
Parton saturation effects to the Drell-Yan process in the color dipole picture
We report on the results obtained in the study of the parton saturation
effects, taken into account through the multiscattering Glauber-Mueller
approach, applied to the Drell-Yan (DY) process described in the color dipole
picture. As a main result, one shows that those effects play an important role
in the estimates of the DY differential cross section atRHIC energies.Comment: To appear in the proceedings of the VIII International Workshop on
Hadron Physics 200
Charm and bottom production in inclusive double Pomeron exchange in heavy ion collisions at the LHC
The inclusive double Pomeron exchange cross section for heavy quark pair
production is calculated for nucleus-nucleus collisions at the LHC. The present
estimate is based on hard diffractive factorization, corrected by absorptive
corrections and nuclear effects. The theoretical uncertainties for nuclear
collisions are investigated and a comparison to other approaches is presented.
The production channels producing a similar final state configuration are
discussed as well.Comment: 7 pages, 3 tables. Final version to be published in Physical Review
Educação ambiental para desenvolvimento sustentável em assentamentos rurais: conribuições de um estudo de representações sociais.
A reforma agrária no Brasil vem sendo discutida há mais de quarenta anos. A partir da Nova República surge o Movimento dos Trabalhadores Sem-Terra, o MST e, com ele, maior organização dos trabalhadores rurais e urbanos e a ampliação do número de ocupações de terras ociosas. A “ocupação”, a “resistência” e a “produção” exigem convívio coletivo. Portanto, é um processo educativo. Este artigo apresenta dois temas: o “trabalho coletivo” e o “uso de tecnologias”, sobre os quais se aglutinam diferentes representações dos agricultores assentados da Fazenda Ipanema, em Iperó, Estado de São Paulo. O conhecimento destas representações indica caminhos para projetos de educação ambiental que se proponham tanto a fortalecer a autonomia e a participação social, quanto à busca de modelos agrossilvopastoris alternativos e mais sustentáveis
On the renormalization of the electroweak chiral Lagrangian with a Higgs
We consider the scalar sector of the effective non-linear electroweak
Lagrangian with a light "Higgs" particle, up to four derivatives in the chiral
expansion. The complete off-shell renormalization procedure is implemented,
including one loop corrections stemming from the leading two-derivative terms,
for finite Higgs mass. This determines the complete set of independent chiral
invariant scalar counterterms required for consistency; these include bosonic
operators often disregarded. Furthermore, new counterterms involving the Higgs
particle which are apparently chiral non-invariant are identified in the
perturbative analysis. A novel general parametrization of the pseudoescalar
field redefinitions is proposed, which reduces to the various usual ones for
specific values of its parameter; the non-local field redefinitions reabsorbing
all chiral non-invariant counterterms are then explicitly determined. The
physical results translate into renormalization group equations which may be
useful when comparing future Higgs data at different energies
Aspects of the Unitarized Soft Multipomeron Approach in DIS and Diffraction
We study in detail the main features of the unitarized Regge model (CFKS),
recently proposed to describe the small- domain. It takes into account a
two-component description with two types of unitarized contributions: one is
the multiple pomeron exchange contribution, interacting with the large dipole
configurations, and the other one consists of a unitarized dipole cross
section, describing the interaction with the small size dipoles. We analyze the
ratio between soft and hard pieces as a function of the virtuality, and also
compare the resulting dipole cross section to that from the saturation model.
Diffraction dissociation is also considered, showing the scaling violations in
diffractive DIS and estimating the corresponding logarithmic slope.Comment: 14 pages, 5 postscript figures. Version to be published in Eur. Phys.
J.
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