28,013 research outputs found
Particle Production in Heavy Ion Collisions
The status of thermal model descriptions of particle production in heavy ion
collisions is presented. We discuss the formulation of statistical models with
different implementation of the conservation laws and indicate their
applicability in heavy ion and elementary particle collisions. We analyze
experimental data on hadronic abundances obtained in ultrarelativistic heavy
ion collisions, in a very broad energy range starting from RHIC/BNL ( A GeV), SPS/CERN ( A GeV) up to AGS/BNL ( A GeV) and SIS/GSI ( A GeV) to test equilibration
of the fireball created in the collision. We argue that the statistical
approach provides a very satisfactory description of experimental data covering
this wide energy range. Any deviations of the model predictions from the data
are indicated. We discuss the unified description of particle chemical
freeze--out and the excitation functions of different particle species. At SPS
and RHIC energy the relation of freeze--out parameters with the QCD phase
boundary is analyzed. Furthermore, the application of the extended statistical
model to quantitative understanding of open and hidden charm hadron yields is
considered.Comment: Invited review for Quark Gluon Plasma 3, eds. R. C. Hwa and Xin-Nian
Wang, World Scientific Publishin
Statistical hadronization of charm at SPS, RHIC and LHC
We study the production of charmonia and charmed hadrons for nucleus-nucleus
collisions at SPS, RHIC, and LHC energies within the framework of the
statistical hadronization model. Results from this model are compared to the
observed centrality dependence of J/psi production at SPS energy. We further
provide predictions for the centrality dependence of the production of open and
hidden charm mesons at RHIC and LHC.Comment: Contribution to Quark Matter 2002, 4 pages, 3 figures; revised
version including charmed hyperons (omitted in v1
Excitations of Bose-Einstein condensates in optical lattices
In this paper we examine the excitations observable in atoms confined in an
optical lattice around the superfluid-insulator transition. We use increases in
the number variance of atoms, subsequent to tilting the lattice as the primary
diagnostic of excitations in the lattice. We show that this locally determined
quantity should be a robust indicator of coherence changes in the atoms
observed in recent experiments. This was found to hold for commensurate or
non-commensurate fillings of the lattice, implying our results will hold for a
wide range of physical cases. Our results are in good agreement with the
quantitative factors of recent experiments. We do, howevers, find extra
features in the excitation spectra. The variation of the spectra with the
duration of the perturbation also turns out to be an interesting diagnostic of
atom dynamics.Comment: 6 pages, 7 figures, using Revtex4; changes to version 2: new data and
substantial revision of tex
The statistical model in Pb-Pb collisions at the LHC
We briefly review the predictions of the thermal model for hadron production
in comparison to latest data from RHIC and extrapolate the calculations to LHC
energy. Our main emphasis is to confront the model predictions with the
recently released data from ALICE at the LHC. This comparison reveals an
apparent anomaly for protons and anti-protons which we discuss briefly. We also
demonstrate that our statistical hadronization predictions for J/
production agree very well with the most recent LHC data, lending support to
the picture in which there is complete charmonium melting in the quark-gluon
plasma (QGP) followed by statistical generation of J/ mesons at the phase
boundary.Comment: 4 pages, 3 figures, proceedings of QM201
Confronting LHC data with the statistical hadronization model
The most recent data from the CERN LHC are compared with calculations within
the statistical hadronization model. The parameters temperature und baryon
chemical potential are fitted to the data. The best fit yields a temperature of
156 MeV, slightly below the expectation from RHIC data. Proton yields are
nearly three standard deviations below this fit and possible reasons are
discussed.Comment: Proceedings of Strange Quark Matter 2013 Conference, to be published
in J. Phys.
Strange Particle Production from SIS to LHC
>1A review of meson emission in heavy ion collisions at incident energies
from SIS up to collider energies is presented. A statistical model assuming
chemical equilibrium and local strangeness conservation (i.e. strangeness
conservation per collision) explains most of the observed features.
Emphasis is put onto the study of and emission at low incident
energies. In the framework of this statistical model it is shown that the
experimentally observed equality of and rates at
``threshold-corrected'' energies is due to a
crossing of two excitation functions. Furthermore, the independence of the
to ratio on the number of participating nucleons observed between
SIS and RHIC is consistent with this model.
It is demonstrated that the production at SIS energies occurs
predominantly via strangeness exchange and this channel is approaching chemical
equilibrium. The observed maximum in the excitation function is
also seen in the ratio of strange to non-strange particle production. The
appearance of this maximum around 30 GeV is due to the energy
dependence of the chemical freeze-out parameters and .Comment: Presented at the International Workshop "On the Physics of the
Quark-Gluon Plasma", Palaiseau, France, September 2001. 10 pages, 8 figure
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