202 articles – 1867 Notices  [english version]
 HAL : in2p3-00268013, version 1
 arXiv : 0803.3940
 20th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2008 (QM 2008), Jaipur : Inde (2008)
 Saturation of $E_T/N_{ch}$ and Freeze-Out Criteria in Heavy-Ion Collisions
 (2008)
 The pseudorapidity densities of transverse energy, the charged particle multiplicity and their ratios, $E_T/N_{ch}$, are estimated at mid-rapidity, in a statistical-thermal model based on chemical freeze-out criteria, for a wide range of energies from GSI-AGS-SPS to RHIC. It has been observed that in nucleus-nucleus collisions, $E_T/N_{ch}$ increases rapidly with beam energy and remains approximately constant at about a value of 800 MeV for beam energies from SPS to RHIC. $E_T/N_{ch}$ has been observed to be almost independent of centrality at all measured energies. The statistical-thermal model describes the energy dependence as well as the centrality independence, qualitatively well. The values of $E_T/N_{ch}$ are related to the chemical freeze-out criterium, $E/N \approx 1 GeV$ valid for primordial hadrons. We have studied the variation of the average mass $(), N_{decays}/N_{primordial}, N_{ch}/N_{decays}$ and $E_T/N_{ch}$ with $\sqrt{s_{NN}}$ for all freeze-out criteria discussed in literature. These observables show saturation around SPS and higher $\sqrt{s_{NN}}$, like the chemical freeze-out temperature ($T_{ch}$).
 Thème(s) : Physique/Physique des Hautes Energies - PhénoménologiePhysique/Physique Nucléaire Expérimentale
 Lien vers le texte intégral : http://fr.arXiv.org/abs/0803.3940
 in2p3-00268013, version 1 http://hal.in2p3.fr/in2p3-00268013 oai:hal.in2p3.fr:in2p3-00268013 Contributeur : Dominique Girod <> Soumis le : Lundi 31 Mars 2008, 08:56:43 Dernière modification le : Jeudi 18 Septembre 2008, 10:39:01