4,204 research outputs found
Heavy-Ion Physics with ALICE
The ALICE detector, expected to start operating at the Large Hadron Collider this year, was designed specifically for the study of heavy-ion collisions. In this paper we recall the main features of the apparatus and give some examples of the expected physics performance
Multi-strange particle production in relativistic heavy ion collisions at GeV
We present preliminary STAR results on measurements of multi-strange
particles , and their anti-particles from Au+Au and Cu+Cu at
GeV collisions. In order to better understand the role of
strangeness enhancement in nucleus-nucleus collisions and its scaling
properties with system size, we compare the results from Au+Au and Cu+Cu
reactions for different event centrality classes. Strangeness enhancement is
discussed in the context of multi-strange to pion ratios. Finally,
ratio is shown for different systems and energies for a
systematic study
Strangeness production within Parton-Hadron-String Dynamics (PHSD)
The Parton-Hadron-String Dynamics (PHSD) transport approach consistently
simulates the full evolution of a relativistic heavy-ion collision from the
initial hard scatterings string formation through the dynamical deconfinement
phase transition to the quark gluon plasma (QGP), to the hadronization and to
subsequent interactions in the hadronic phase. The transport theoretical
description of quarks and gluons is based on a dynamical quasiparticle model
for partons matched to reproduce recent lattice QCD results in thermodynamic
equilibrium. The transition from partonic to hadronic degrees of freedom is
described by covariant transition rates for the fusion of quark-antiquark pairs
or three quarks (antiquarks). Studying Pb+Pb reactions from 40 to 158 A GeV, we
find that at most 40% of the collision energy is stored in the dynamics of the
partons. This implies that a large fraction of non-partonic, i.e. hadronic or
string-like matter, which can be viewed as a hadronic corona, is present in
these reactions, thus neither hadronic nor purely partonic models can be
employed to extract physical conclusions in comparing model results with data.
On the other hand, comparing the PHSD results to those of the Hadron-String
Dynamics (HSD) approach without the phase transition to QGP, we observe that
the existence of the partonic phase has a sizeable influence on the transverse
mass distribution of final kaons due to the repulsive partonic mean fields and
initial partonic scattering. Furthermore, we find a significant effect of the
QGP on the production of multi-strange antibaryons due to a slightly enhanced
s+sbar pair production in the partonic phase from massive time-like gluon decay
and to a more abundant formation of strange antibaryons in the hadronization
process.Comment: Talk given at the International Conference Strangeness in Quark
Matter 2009 (SQM 09
Centrality and Energy Dependence of Proton, Light Fragment and Hyperon Production
Recent results of the NA49 collaboration are discussed. These include the
energy dependence of stopping and the production of the light fragments t and
3He. New data on the system size dependence of hyperon production at 40A and
158AGeV are also presented.Comment: 4 pages, Quark Matter 2006 proceeding
Lateral Effects in Fermion Antibunching
Lateral effects are analyzed in the antibunching of a beam of free
non-interacting fermions. The emission of particles from a source is
dynamically described in a 3D full quantum field-theoretical framework. The
size of the source and the detectors, as well as the temperature of the source
are taken into account and the behavior of the visibility is scrutinized as a
function of these parameters.Comment: 22 pages, 4 figure
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
Design and test of the final ALICE SDD CARLOS end ladder board
The paper presents the design and test of the final prototype of the CARLOS (Compression And Run Length Encoding Subsystem) end ladder board that is going to be used in the ALICE experiment at CERN. This board is able to compress data coming from one Silicon Drift Detector (SDD) front-end electronics and to send them towards the data concentrator card CARLOSrx in counting room via a 800 Mb/s optical link. The board design faces several constraints, mainly size (54x49 mm) and radiation tolerance: for this reason the board contains several CERN developed ASICs. A test setup has been realized for selecting the good devices among the 500 cards already produced
Strangeness enhancements at central rapidity in 40 A GeV/c Pb-Pb collisions
Results are presented on neutral kaon, hyperon and antihyperon production in
Pb-Pb and p-Be interactions at 40 GeV/c per nucleon. The enhancement pattern
follows the same hierarchy as seen in the higher energy data - the enhancement
increases with the strangeness content of the hyperons and with the centrality
of collision. The centrality dependence of the Pb-Pb yields and enhancements is
steeper at 40 than at 158 A GeV/c. The energy dependence of strangeness
enhancements at mid-rapidity is discussed.Comment: 15 pages, 10 figures and 3 tables. Presented at International
Conference on Strangeness in Quark Matter (SQM2009), Buzios, Rio de Janeiro,
Brazil, 27 Sept - 2 Oct 2009. Submitted to J.Phys.G: Nucl.Part.Phys, one
reference adde
System Size Dependence of Particle Production at the SPS
Recent results on the system size dependence of net-baryon and hyperon
production as measured at the CERN SPS are discussed. The observed Npart
dependences of yields, but also of dynamical properties, such as average
transverse momenta, can be described in the context of the core corona
approach. Other observables, such as antiproton yields and net-protons at
forward rapidities, do not follow the predictions of this model. Possible
implications for a search for a critical point in the QCD phase diagram are
discussed. Event-by-event fluctuations of the relative core to corona source
contributions might influence fluctuation observables (e.g. multiplicity
fluctuations). The magnitude of this effect is investigated.Comment: 10 pages, 4 figurs. Proceedings of the 6th International Workshop on
Critical Point and Onset of Deconfinement in Dubna, Aug. 201
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