1,782 research outputs found
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.
Transition from Baryon- to Meson-Dominated Freeze Out -- Early Decoupling around 30 A GeV?
The recently discovered sharp peak in the excitation function of the K+/pi+
ratio around 30 A GeV in relativistic heavy-ion collisions is discussed in the
framework of the Statistical Model. In this model, the freeze-out of an ideal
hadron gas changes from a situation where baryons dominate to one with mainly
mesons. This transition occurs at a temperature T = 140 MeV and baryon chemical
potential mu(B) = 410 MeV corresponding to an energy of sqrt(s) = 8.2 GeV. The
calculated maximum in the K+/pi+ ratio is, however, much less pronounced than
the one observed by the NA49 Collaboration. The smooth increase of the K-/pi-
ratio with incident energy and the shape of the excitation functions of the
Lambda/pi+, Xi-/pi+ and Omega/pi ratios all exhibiting maxima at different
incident energies, is consistent with the presently available experimental
data. The measured K+/pi+ ratio exceeds the calculated one just at the incident
energy when the freeze-out condition is changing.
We speculate that at this point freeze-out might occur in a modified way. We
discuss a scenario of an early freeze-out which indeed increases K+/pi+ ratio
while most other particle ratios remain essentially unchanged. Such an early
freeze-out is supported by results from HBT studies.Comment: 8 pages, 5 figures, SQM2006 conference, Los Angeles, March 200
Centrality dependence of thermal parameters in heavy-ion collisions at SPS and RHIC
We analyze the centrality dependence of thermal parameters describing hadron
multiplicities, hadron spectra and dilepton spectra in heavy-ion collisions at
SPS and RHIC energies.Comment: contribution to the Int. Workshop XXX on Gross Properties of Nuclei
and Nuclear Excitations: Ultrarelativistic Heavy-Ion Collisions, Hirschegg,
Jan. 13 - 19, 200
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
Strangeness Saturation: Dependence on System-Size, Centrality and Energy
The dependence of the strangeness saturation factor on the system size,
centrality and energy is studied in relativistic heavy-ion collisions.Comment: contribution for Proc. 19th Winter Workshop on Nuclear Dynamics,
Breckenridge, February 8-15, 200
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