1,345 research outputs found
Monte Carlo model for nuclear collisions from SPS to LHC energies
A Monte Carlo model to simulate nuclear collisions in the energy range going
from SPS to LHC, is presented. The model includes in its initial stage both
soft and semihard components, which lead to the formation of color strings.
Collectivity is taken into account considering the possibility of strings in
color representations higher than triplet or antitriplet, by means of string
fusion. String breaking leads to the production of secondaries. At this point,
the model can be used as initial condition for further evolution by a transport
model. In order to tune the parameters and see the results in nucleus-nucleus
collisions, a naif model for rescattering of secondaries is introduced. Results
of the model are compared with experimental data, and predictions for RHIC and
LHC are shown.Comment: LaTeX, 48 pages, 6 tables, 15 postscript figures included using
epsfi
Origen floral de mieles producidas en tres comarcas geopolíticas Gallegas
XV lnternational A.P.L.E. Symposium of Palynolog
Transverse momentum distributions and their forward- backward correlations in the percolating colour string approach
The forward-backward correlations in the distributions, which present a
clear signature of non-linear effects in particle production, are studied in
the model of percolating colour strings. Quantitative predictions are given for
these correlations at SPS, RHIC and LHC energies. Interaction of strings also
naturally explains the flattening of distributions and increase of
with energy and atomic number for nuclear collisionsComment: 6 pages in LaTex, 3 figures in Postscrip
Nuclear collisions at the Future Circular Collider
The Future Circular Collider is a new proposed collider at CERN with
centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at
assessing its physics potential and technical feasibility. Here we focus on
updates in physics opportunities accessible in pA and AA collisions not covered
in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon
saturation studies, novel hard probes of QCD matter, and photon-induced
collisions.Comment: 4 pages, 5 figures, proceedings of Quark Matter 201
Holographic Screening Length in a Hot Plasma of Two Sphere
We study the screening length of a quark-antiquark pair moving in a hot
plasma living in two sphere manifold using AdS/CFT correspondence where
the background metric is four dimensional Schwarzschild-AdS black hole. The
geodesic solution of the string ends at the boundary is given by a stationary
motion in the equatorial plane as such the separation length of
quark-antiquark pair is parallel to the angular velocity . The
screening length and the bound energy are computed numerically using
Mathematica. We find that the plots are bounded from below by some functions
related to the momentum transfer of the drag force configuration. We
compare the result by computing the screening length in the quark-antiquark
reference frame where the gravity dual are "Boost-AdS" and Kerr-AdS black
holes. Finding relations of the parameters of both black holes, we argue that
the relation between mass parameters of the Schwarzschild-AdS black
hole and of the Kerr-AdS black hole in high temperature is given by
, where is the angular momentum
parameter.Comment: Major revision: title changed, adding authors, 13 pages, 8 figures,
etc. Accepted for publication in European Physical Journal
Measuring beauty production in Pb-Pb collisions at the LHC via single electrons in ALICE
We present the expected ALICE performance for the measurement of the
p_t-differential cross section of electrons from beauty decays in central Pb-Pb
collisions at the LHC.Comment: 4 pages, 2 figures, proceeding of poster presentation at "Quark
Matter 2005
Shear viscosity and chemical equilibration of the QGP
We have investigated, in the frame work of the transport approach, different
aspects of the QGP created in Heavy Ion Collisions at RHIC and LHC energies.
The shear viscosity has been calculated by using the Green-Kubo relation
at the cascade level. We have compared the numerical results for
obtained from the Green-Kubo correlator with the analytical formula in both the
Relaxation Time Approximation (RTA) and the Chapman-Enskog approximation (CE).
From this comparison we show that in the range of temperature explored in a
Heavy Ion collision the RTA underestimates the viscosity by about a factor of
2, while a good agreement is found between the CE approximation and Gree-Kubo
relation already at first order of approximation. The agreement with the CE
approximation supplies an analytical formula that allows to develop kinetic
transport theory at fixed shear viscosity to entropy density ratio, .
We show some results for the build up of anisotropic flows in a
transport approach at fixed shear viscosity to entropy density ratio, .
We study the impact of a T-dependent on the generation of the
elliptic flows at both RHIC and LHC. We show that the transport approach
provides, in a unified way, a tool able to naturally describe the
in a wide range of , including also the description of
the rise and fall and saturation of the observed at LHC.
Finally, we have studied the evolution of the quark-gluon composition employing
a Boltzmann-Vlasov transport approach that include: the mean fields dynamics,
associated to the quasi-particle model, and the elastic and inelastic
collisions for massive quarks and gluons. Following the chemical evolution from
an initial gluon dominated plasma we predict a quark dominance close to
paving the way to an hadronization via quark coalescence.Comment: 15 pages, 10 figures, Invited Talk given by S. Plumari at the 11th
International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio,
Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in
Journal of Physics: Conference Series (JPCS
Charged Current Neutrino Cross Section and Tau Energy Loss at Ultra-High Energies
We evaluate both the tau lepton energy loss produced by photonuclear
interactions and the neutrino charged current cross section at ultra-high
energies, relevant to neutrino bounds with Earth-skimming tau neutrinos, using
different theoretical and phenomenological models for nucleon and nucleus
structure functions. The theoretical uncertainty is estimated by taking
different extrapolations of the structure function F2 to very low values of x,
in the low and moderate Q2 range for the tau lepton interaction and at high Q2
for the neutrino-nucleus inelastic cross section. It is at these extremely low
values of x where nuclear shadowing and parton saturation effects are unknown
and could be stronger than usually considered. For tau and neutrino energies
E=10^9 GeV we find uncertainties of a factor 4 for the tau energy loss and of a
factor 2 for the charged current neutrino-nucleus cross section.Comment: 20 pages and 11 figure
Jet quenching via jet collimation
The strong modifications of dijet properties in heavy ion collisions measured
by ATLAS and CMS provide important constraints on the dynamical mechanisms
underlying jet quenching. In this work, we show that the transport of soft
gluons away from the jet cone - jet collimation - can account for the observed
dijet asymmetry with values of that lie in the expected order of
magnitude. Further, we show that the energy loss attained through this
mechanism results in a very mild distortion of the azimuthal angle dijet
distribution.Comment: 4 pages, 2 figures; Proceedings of the "Quark Matter 2011" conferenc
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