Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 21: Heavy Ions II
HK 21.10: Vortrag
Dienstag, 9. März 2004, 18:00–18:15, F
Interpretation of the system-size dependence of strangeness production in A+A collisions at 158 AGeV — •C. Höhne1, F. Pühlhofer1, I. Kraus2, M. Gazdzicki3, H. Ströbele3, and R. Stock3 — 1Fachbereich Physik, Universität Marburg — 2GSI, Darmstadt — 3Institut für Kernphysik, Universität Frankfurt
New data from the NA49 experiment at the CERN-SPS support the interpretation that in central Pb+Pb collisions above 30 AGeV a partonic phase is created in the early stage of the reaction. This conclusion is based on the non monotonic devolution of the energy dependence of strangeness production. Complementary information is obtained from the system-size dependence recently measured by NA49 (p+p, C+C, Si+Si, Pb+Pb at 158 AGeV).
The data show a steep rise of the relative strangeness production as a function of the number of participating nucleons reaching a saturation value at Npart∼ 60. Qualitatively, this scenario is expected from statistical models in which the relative strangeness content rises with increasing volume due to vanishing constraints imposed by strict local flavor conservation. In this work an attempt is made to understand this phenomenon starting from a microscopic view of the reaction. Using results from model calculations the hypothesis is formulated that coherent partonic subsystems of increasing size are formed decaying as one quantum-mechanical object. Hadron abundances resulting from this decay can be described with statistical models.