3,143 research outputs found
Gluon shadowing in the Glauber-Gribov model at HERA
We calculate shadowing using new data on the gluon density of the Pomeron
recently measured with high precision at HERA. The calculations are made in a
Glauber-Gribov framework and Pomeron tree-diagrams are summed up within a
unitarity-conserving procedure. The total cross section of \vphot A
interaction is then found in a parameter-free description, employing gluon
diffractive and inclusive distribution functions as input. A strong shadowing
effect is obtained, in good agreement with several other models. Impact
parameter dependence of gluon shadowing is also presented.Comment: 18 pages, 6 figures; references added, discussion of model enlarged,
calculation of low-x contribution corrected; to appear in Phys. Let
Gluon shadowing and unitarity effects
New data from HERA experiment on deep inelastic scattering have been used to
parametrize nucleon and Pomeron structure functions. Within the Gribov theory,
the parameterizations were employed to calculate gluon shadowing for various
heavy ions. The latter was compared with predictions from other models.
Calculations of multiplicity reduction due to gluon shadowing for d+Au
collisions at forward rapidities at =200 GeV are in good agreement
with BRAHMS data on the nuclear modification factor.Comment: 5 pages, 4 figures, submitted to Acta Physica Hungarica A, Quark
Matter 2005 poster session proceedings; minor changes in the text adde
Revisiting the method to obtain the mechanical properties of hydrided fuel cladding in the hoop direction
The method reported in the literature to calculate the stress–strain curve of nuclear fuel cladding from ring tensile test is revisited in this paper and a new alternative is presented. In the former method, two universal curves are introduced under the assumption of small strain. In this paper it is shown that these curves are not universal, but material-dependent if geometric nonlinearity is taken into account. The new method is valid beyond small strains, takes geometric nonlinearity into consideration and does not need universal curves. The stress–strain curves in the hoop direction are determined by combining numerical calculations with experimental results in a convergent loop. To this end, ring tensile tests were performed in unirradiated hydrogen-charged samples. The agreement among the simulations and the experimental results is excellent for the range of concentrations tested (up to 2000 wppm hydrogen). The calculated stress–strain curves show that the mechanical properties do not depend strongly on the hydrogen concentration, and that no noticeable strain hardening occurs. However, ductility decreases with the hydrogen concentration, especially beyond 500 wppm hydrogen. The fractographic results indicate that as-received samples fail in a ductile fashion, whereas quasicleavage is bserved in the hydrogen-charged samples
Modeling the jet quenching, thermal resonance production and hydrodynamical flow in relativistic heavy ion collisions
The event topology in relativistic heavy ion collisions is determined by
various multi-particle production mechanisms. The simultaneous model treatment
of different collective nuclear effects at high energies (such as a hard
multi-parton fragmentation in hot QCD-matter, thermal resonance production,
hydrodynamical flows, etc.) is actual but rather complicated task. We discuss
the simulation of the above effects by means of Monte-Carlo model HYDJET++.Comment: Talk given at Workshop "Hot Quarks 2010" (La Londe Les Maures,
France, June 21-26, 2010); 4 pages including 2 figures as EPS-files; prepared
using LaTeX package for publication in Journal of Physics: Conference Serie
BRAHMS Overview
A brief review of BRAHMS measurements of bulk particle production in RHIC
Au+Au collisions at is presented, together with some
discussion of baryon number transport. Intermediate measurements in
different collision systems (Au+Au, d+Au and p+p) are also discussed in the
context of jet quenching and saturation of the gluon density in Au ions at RHIC
energies. This report also includes preliminary results for identified
particles at forward rapidities in d+Au and Au+Au collisions.Comment: 8 pages 6 figures, Invited plenary talk at 5th International
Conference on Physics and Astrophysics of Quark Gluon Plasma (ICPAQGP 2005),
Salt Lake City, Kolkata, India, 8-12 Feb 200
Color Skyrmions in the Quark-Gluon Plasma
We consider the general formulation of nonabelian fluid dynamics based on
symmetry considerations. We point out that, quite generally, this admits
solitonic excitations which are the color analog of skyrmions. Some general
properties of the solitons are discussed.Comment: LaTeX, 13 pages, references adde
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