Hadronic observables from SIS to SPS energies: anything strange with strangeness?
We calculate p, ±,K± and (+ 0) rapidity distributions and compare to experimental data from SIS to SPS energies within the UrQMD and HSD transport approaches that are both based on string, quark, diquark (q, ¯q, qq, ¯q ¯q) and hadronic degrees of freedom. The two transport models do not include any explicit phase transition to a quark-gluon plasma (QGP). It is found that both approaches agree rather well with each other and with the experimental rapidity distributions for protons, s, ± and K±. In- spite of this apparent agreement both transport models fail to reproduce the maximum in the excitation function for the ratio K+/ + found experimen- tally between 11 and 40 A·GeV. A comparison to the various experimental data shows that this failure is dominantly due to an insu cient description of pion rapidity distributions rather than missing strangeness . The modest di erences in the transport model results on the other hand can be attributed to di erent implementations of string formation and frag- mentation, that are not su ciently controlled by experimental data for the elementary reactions in vacuum.
|Author:||H. Weber, Elena L. Bratkovskaya, Wolfgang Cassing, Horst Stöcker|
|Date of Publication (online):||15.11.2005|
|Year of first Publication:||2002|
|Publishing Institution:||Univ.-Bibliothek Frankfurt am Main|
|Tag:||Chiral symmetries ; Kernreaktion Modell und Methoden ; Meson production; Relativistische Kollisionen des schwere Ions |
Chiral symmetries ; Meson production; Nuclear-reaction models and methods ; Relativistic heavy-ion collisions
|Dewey Decimal Classification:||530 Physik|
|Licence (German):||Veröffentlichungsvertrag für Publikationen ohne Print on Demand|