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S. Wheaton

Publications and source records attributed to S. Wheaton.

27 records · Page 2Linked to original sources

Transition from Baryonic to Mesonic Freeze-Out

The recently discovered sharp peak in the K+/pi+ ratio 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 happens at sqrt{s_{NN}} = 8.16 GeV, temperature T = 140 MeV and baryon chemical potential mu_B = 410 MeV. The maximum in the Lambda/pi ratio is well reproduced by the statistical model, but the change in the K+/pi+ ratio is much less pronounced than the one observed by the NA49 collaboration. Further experimental tests are proposed to clarify the nature of the transition. In particular, the maxima expected in the statistical model for the Xi/pi and Omega/pi ratios occur at slightly higher beam energies than the maxima for the Lambda/pi and K+/pi+ ratios.

hep-ph↗

Centrality Dependence of Thermal Parameters Deduced from Hadron Multiplicities in Au + Au Collisions at sqrt{s_{NN}} = 130 GeV

We analyse the centrality dependence of thermal parameters deduced from hadron m ultiplicities in Au + Au collisions at $\sqrt{s_{NN}} = 130 GeV$. While the chemical freeze-out temperature and chemical potentials are found to be roughly centrality-independent, the strangeness saturation factor $γ_S$ increases with participant number towards unity, supporting the assumption of equilibrium freeze-out conditions in central collisions.

hep-ph↗

System-size dependence

The final state in The final state in heavy-ion collisions has a higher degree of strangeness saturation than the one produced in collisions between elementary particles like p-p or p-$\bar{p}$. A systematic analysis of this phenomenon is made for C-C, Si-Si and Pb-Pb collisions at the CERN SPS collider and for $Au-Au$ collisions at RHIC and at AGS energies. Strangeness saturation is shown to increase smoothly with the number of participants at AGS, CERN and RHIC energies.

hep-ph↗

Strangeness Saturation: Energy- and System-Size Dependence

Relativistic heavy-ion collisions lead to a final state which has a higher degree of strangeness saturation than those of elementary collisions. A systematic analysis of this phenomenon, based on the strangeness saturation factor, is made for C+C, Si+Si and Pb+Pb collisions at the CERN SPS collider and for Au+Au collisions at RHIC energies. Strangeness saturation is shown to increase with the number of participants within a colliding system, at both CERN SPS and RHIC energies. The saturation observed in central collisions of lighter nuclei deviates from that seen in peripheral collisions of heavier nuclei with an equivalent participant number, which could be due to the difference in nuclear density.

hep-ph↗

Centrality Dependence of Thermal Parameters in Heavy-Ion Collisions at CERN-SPS

The centrality dependence of thermal parameters, characterizing the hadron multiplicities, is determined phenomenologically for lead-on-lead collisions at CERN-SPS for a beam energy of 158 AGeV. The strangeness equilibration factor shows a clear, approximately linear, increase with increasing centrality, while the freeze-out temperature and chemical potential remain constant.

nucl-th↗