2,723 research outputs found
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
Charmonium Production from the Secondary Collisions at LHC Energy
We consider the charmonium production in thermalized hadronic medium created
in ultrarelativistic heavy ion collisions at LHC energy.
The calculations for the secondary and production by annihilation are performed within a kinetic model taking into account the
space-time evolution of a longitudinally and transversely expanding medium. We
show that the secondary charmonium production appears almost entirely during
the mixed phase and it is very sensitive to the charmonium dissociation cross
section with co-moving hadrons. Within the most likely scenario for the
dissociation cross section of the mesons their regeneration in the
hadronic medium will be negligible. The secondary production of mesons
however, due to their large cross section above the threshold, can
substantially exceed the primary yield.Comment: ps file 11
Thermal description of hadron production in e+e- collisions revisited
We present a comprehensive analysis of hadron production in e+e- collisions
at different center-of-mass energies in the framework of the statistical model
of the hadron resonance gas. The model is formulated in the canonical ensemble
with exact conservation of all relevant quantum numbers. The parameters of the
underlying model were determined using a fit to the average multiplicities of
the latest measurements at = 10, 29-35, 91 and 130-200 GeV. The
results demonstrate that, within the accuracy of the experiments, none of the
data sets is satisfactorily described with this approach, calling into question
the notion that particle production in e+e- collisions is thermal in origin.Comment: 13 pages, 3 figures; v2: final version accepted for publication in
Phys. Lett.
Hadron production in Au-Au collisions at RHIC
We present an analysis of particle production yields measured in central
Au-Au collisions at RHIC in the framework of the statistical thermal model. We
demonstrate that the model extrapolated from previous analyses at SPS and AGS
energy is in good agreement with the available experimental data at GeV implying a high degree of chemical equilibration. Performing a
fit to the data, the range of thermal parameters at chemical freezeout
is determined. At present, the best agreement of the model and the data is
obtained with the baryon chemical potential MeV and
temperature MeV. More ratios, such as multistrange baryon to
meson, would be required to further constrain the chemical freezeout
conditions. Extrapolating thermal parameters to higher energy, the predictions
of the model for particle production in Au-Au reactions at GeV
are also given.Comment: Final version, minor changes to text and figures. To appear in Phys.
Lett.
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
Charmonium and open charm production in nuclear collisions at SPS/FAIR energies and the possible influence of a hot hadronic medium
We provide predictions for charmonium and open charm production in nuclear
collisions at SPS/FAIR energies within the framework of the statistical
hadronization model. The increasing importance at lower energies of Lambda_c
production is demonstrated and provides a challenge for future experiments. We
also demonstrate that, because of the large charm quark mass and the different
timescales for charm quark and charmed hadron production, possible
modifications of charmed hadrons in the hot hadronic medium do not lead to
measurable changes in cross sections for D-meson production. A possible
influence of medium effects can be seen, however, in yields of charmonium.
These effects are visible at all energies and results are presented for the
energy range between charm threshold and RHIC energy.Comment: 12 pages, 4 figures; v2: slightly revised text and updated
calculations; v3: slightly enhanced discussion, one more ref.; data file with
calculations will be available at
http://www-linux.gsi.de/~andronic/physics/charm
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
Canonical aspects of strangeness enhancement
Strangeness enhancement (SE) in heavy ion collisions can be understood in the
statistical model on the basis of canonical suppression. In this formulation,SE
is a consequence of the transition from canonical to the asymptotic grand
canonical limit and is predicted to be a decreasing function of collision
energy. This model predictions are consistent with the recent NA49 data on
enhancement at GeV.Comment: 4 pages, 4 figures. To appear in the proceedings of Quark Matter 2002
(Nantes, France
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