1996/08/31 by Nelmara Arbex, N. Arbex, U. Ornik +4 · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #High-Energy Particle Collisions Research #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1016/s0370-2693(96)01289-0
published as Phys.Lett. B391 (1997) 465-468 · 8 pages and 2 figures, submmited to Phys. Lett. B. This reviewed version (Nov.29,1996) contains more details about the model simulated efficiency considering the experimental detection conditions. Other small modifications were made
arxiv created 1996/12/06 · openalex publication_date 1997/01/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We calculate the pi-/pi+ ratio for Pb+Pb at CERN/SPS energies and for Au+Au at BNL/AGS energies using a (3+1) dimensional hydrodynamical model. Without consideration of Coulomb effect an enhancement of this ratio at low mt is found compatible with that observed in these experiments. Our calculations are based on previous (3+1) dimensional hydrodynamical simulations (HYLANDER), which described many other aspects of experimental data. In this model the observed enhancement is a consequence of baryon and strangeness conservation and of chemical equilibration of the system and is caused by the decay of produced hyperons, which leads to a difference in the total number of positive and negative pions as well. Based on the same approach, we also present results for the pi-/pi+ ratio for S+S (CERN/SPS) collisions, where we find a similar effect. The absence of the enhancement of the pi-/pi+ ratio in the S+S data presented by the NA44 Collaboration, if confirmed, could indicate that chemical equilibration has not yet been estabilished in this reaction.