Year of publication
- 2005 (2) (remove)
- Particle number fluctuations in high energy nucleus-nucleus collisions from microscopic transport approaches (2005)
- Event-by-event multiplicity fluctuations in nucleus-nucleus collisions are studied within the HSD and UrQMD transport models. The scaled variances of negative, positive, and all charged hadrons in Pb+Pb at 158 AGeV are analyzed in comparison to the data from the NA49 Collaboration. We find a dominant role of the fluctuations in the nucleon participant number for the final hadron multiplicity fluctuations. This fact can be used to check di erent scenarios of nucleus-nucleus collisions by measuring the final multiplicity fluctuations as a function of collision centrality. The analysis reveals surprising e ects in the recent NA49 data which indicate a rather strong mixing of the projectile and target hadron production sources even in peripheral collisions. PACS numbers: 25.75.-q,25.75.Gz,24.60.-k
- Transverse pressure and strangeness dynamics in relativistic heavy-ion reactions (2005)
- Transverse hadron spectra from proton-proton, proton-nucleus and nucleus-nucleus collisions from 2 AGeV to 21.3 ATeV are investigated within two independent transport approaches (HSD and UrQMD). For central Au+Au (Pb+Pb) collisions at energies above E lab ~ 5 AGeV, the measured K +- transverse mass spectra have a larger inverse slope parameter than expected from the default calculations. The additional pressure - as suggested by lattice QCD calculations at finite quark chemical potential mu q and temperature T - might be generated by strong interactions in the early pre-hadronic/partonic phase of central Au+Au (Pb+Pb) collisions. This is supported by a non-monotonic energy dependence of v2/pT in the present transport model.