Browsing by Author "Wheaton, S"

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    Centrality dependence of thermal parameters deduced from hadron multiplicities in Au+Au collisions at √sN N = 130 GeV
    (2005) Cleymans, J; Kampfer, B; Kaneta, M; Wheaton, S; Xu, N
    We analyze the centrality dependence of thermal parameters deduced from hadron multiplicities in Au+Au collisions at √sNN = 130 GeV. Although the chemical freeze-out temperature and chemical potentials are found to be roughly centrality independent, the strangeness saturation factor γS increases with participant number toward unity, supporting the assumption of equilibrium freeze-out conditions in central collisions
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    Towards strangeness saturation in central heavy-ion collisions at high energies
    (Elsevier, 2003) Cleymans, J; Kämpfer, B; Wheaton, S
    It is now well established that particle abundances can be described by statistical-thermal models. In such a way, a large number of observables can be reproduced with a small number of parameters, namely the temperature, baryo-chemical potential and a factor measuring the degree of strangeness saturation. Here we focus on the centrality dependence of the hadron multiplicities and adjust the thermal parameters so as to reproduce the experimental data.
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    Transition from baryonic to mesonic freeze-out
    (2005) Cleymans, J; Oeschler, H; Redlich, K; Wheaton, S
    The recently discovered sharp peak in the K+/π+ ratio in relativistic heavy-ion collisions is discussed in the framework of the statistical model. In this model a rapid change is expected as the hadronic gas undergoes a transition from a baryon-dominated to a meson-dominated gas. The transition occurs at a temperature T=140MeV and baryon chemical potential μB=410MeV corresponding to an incident energy of sNN=8.2GeV. The maximum in the Λ/π ratio is well reproduced by the statistical model, but the change in the K+/π+ ratio is much less pronounced than the one observed by the NA49 Collaboration. The calculated smooth increase of the K−/π− ratio and the shape of the Ξ−/π+ and Ω−/π+ ratios exhibiting maxima at different incident energies is consistent with the presently available experimental data. We conclude that the measured particle ratios with 20–30% deviations agree with a hadronic freeze-out scenario. These deviations seem to occur just in the transition from baryon-dominated to meson-dominated freeze-out.