646 research outputs found
Statistical Model and the mesonic-baryonic transition region
The statistical model assuming chemical equilibriumand local strangeness
conservation describes most of the observed features of strange particle
production from SIS up to RHIC. Deviations are found as the maximum in the
measured K+/pi+ ratio is much sharper than in the model calculations. At the
incident energy of the maximum, the statistical model shows that freeze out
changes regime from one being dominated by baryons at the lower energies toward
one being dominated by mesons. It will be shown how deviations from the usual
freeze-out curve influence the various particle ratios. Furthermore, other
observables exhibit also changes just in this energy regime.Comment: 9 pages, 7 figures, CPOD conference proceeding
Conservation Laws and Particle Production in Heavy Ion Collisions
We discuss the role of the conservation laws related with U(1) internal
symmetry group in the statistical model description of particle productions in
ultrarelativistic heavy ion collisions. We derive and show the differences in
particle multiplicities in the canonical and the grand canonical formulation of
quantum number conservation. The time evolution and the approach to chemical
equilibrium in the above ensembles is discussed in terms of kinetic master
equation. The application of the statistical model to the description of
(multi)strange particle yields at GSI/SIS and the SPS energies is also
presented.Comment: Invited talk at International Symposium on Hadron and Nuclei, Seoul,
Korea, 20-22 Feb 200
Statistical Model Predictions for Pb-Pb Collisions at LHC
The systematics of Statistical Model parameters extracted from heavy-ion
collisions at lower energies are exploited to extrapolate in the LHC regime.
Predictions of various particle ratios are presented and particle production in
central Pb-Pb collisions at LHC is discussed in the context of the Statistical
Model. The sensitivity of several ratios on the temperature and the baryon
chemical potential is studied in detail, and some of them, which are
particularly appropriate to determine the chemical freeze-out point
experimentally, are indicated. The impact of feed-down contributions from
resonances, especially to light hadrons, is illustrated.Comment: 5 pages, 2 figures, 1 table, SQM 2006 conference proceedings,
accepted for publication in J. Phys.
On the chemical equilibration of strangeness-exchange reaction in heavy-ion collisions
The strangeness-exchange reaction pi + Y -> K- + N is shown to be the
dynamical origin of chemical equilibration for K- production in heavy-ion
collisions up to beam energies of 10 A GeV. The hyperons occurring in this
process are produced associately with K+ in baryon-baryon and meson-baryon
interactions. This connection is demonstrated by the ratio K-/K+ which does not
vary with centrality and shows a linear correlation with the yield of pions per
participant. At incident energies above AGS this correlation no longer holds
due to the change in the production mechanism of kaons.Comment: 9 pages, 4 figure
Statistical Model Predictions for p+p and Pb+Pb Collisions at LHC
Particle production in p+p and central Pb+Pb collisions at LHC is discussed
in the context of the statistical thermal model. For heavy-ion collisions,
predictions of various particle ratios are presented. The sensitivity of
several ratios on the temperature and the baryon chemical potential is studied
in detail, and some of them, which are particularly appropriate to determine
the chemical freeze-out point experimentally, are indicated. Considering
elementary interactions on the other hand, we focus on strangeness production
and its possible suppression. Extrapolating the thermal parameters to LHC
energy, we present predictions of the statistical model for particle yields in
p+p collisions. We quantify the strangeness suppression by the correlation
volume parameter and discuss its influence on particle production. We propose
observables that can provide deeper insight into the mechanism of strangeness
production and suppression at LHC.Comment: 7 pages, 5 figures, conference contribution to "International school
of nuclear physics", Erice, Sicily, 16 - 24 September 2008; Progress in
Particle and Nuclear Physics, 2009, in pres
Particle production in p-p collisions and prediction for LHC energy
We analyze recent data on particle production yields obtained in p-p
collisions at SPS and RHIC energies within the statistical model. We apply the
model formulated in the canonical ensemble and focus on strange particle
production. We introduce different methods to account for strangeness
suppression effects and discuss their phenomenological verification. We show
that at RHIC the midrapidity data on strange and multistrange particle
multiplicity can be successfully described by the canonical statistical model
with and without an extra suppression effects. On the other hand, SPS data
integrated over the full phase-space require an additional strangeness
suppression factor that is beyond the conventional canonical model. This factor
is quantified by the strangeness saturation parameter or strangeness
correlation volume. Extrapolating all relevant thermal parameters from SPS and
RHIC to LHC energy we present predictions of the statistical model for particle
yields in p-p collisions at sqrt(s) = 14TeV. We discuss the role and the
influence of a strangeness correlation volume on particle production in p-p
collisions at LHC.Comment: 6 pages, 6 figures, 4 tables, submitted to Phys. Rev.
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