Speaker
Herbert Stroebele
(Johann-Wolfgang-Goethe Univ. (DE))
Description
The NA49 collaboration measured the rapidity and
transverse mass distributions of kaons and pions in
Pb+Pb collisions at different centralities. These data are
complemented by results from the small systems C+C
and Si+Si. We find that the centrality dependence of
kaon and pion production is reproduced by microscopic
transport model calculations (HSD and UrQMD2.3)
within 20% or better. The mean transverse mass evolves
with centrality as expected for increased stopping and en-
ergy deposition. The centrality dependence of the widths
of the rapidity distributions in Pb+Pb collisions does not
smoothly connect to results from the small systems p+p,
C+C, and Si+Si. In Pb+Pb collisions the K/π ratios show
a smooth increase with centrality at both beam energies
with saturation setting in around 100-200 (60-100)
wounded nucleons for 40A GeV (158A GeV). This behavior
fits well into the trends observed at lower (AGS)
and higher (RHIC) energies.
Author
Herbert Stroebele
(Johann-Wolfgang-Goethe Univ. (DE))
