Berlin 2005 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 39: Physik mit schweren Ionen

HK 39.6: Talk

Wednesday, March 9, 2005, 15:30–15:45, TU MA144

Centrality Dependence of π⁻– π⁻-correlations in Pb+Pb collisions at 40 and 160 AGeV at the CERN SPS^* — •C. Alt¹, C. Blume¹, P. Dinkelaker¹, D. Flierl¹, V. Friese^2,3, M. Gazdzicki¹, F. Kramer¹, M. Kliemant¹, S. Kniege¹, I. Kraus², B. Lungwitz¹, C. Meurer¹, R. Renfordt¹, A. Richard¹, A. Sandoval², T. Schuster¹, R. Stock¹, C. Strabel¹, and H. Ströbele¹ — ¹Institut für Kernphysik, Universität Frankfurt — ²Gesellschaft für Schwerionenforschung (GSI), Darmstadt — ³Fachbereich Physik der Universität, Marburg

In order to analyse the dependence of hadronic observables on centrality in heavy ion collisions the NA49 experiment collected minimum bias data on Pb+Pb collisions at 40 and 160 AGeV.

The investigation of the momentum correlations of identical bosons (HBT) yields information about the spatial and temporal evolution of the particle emitting source in heavy ion collisions. The dependence of the measured HBT parameters on centrality reflects the freeze-out conditions at various impact parameters. We will present HBT radii in different centrality classes at 40 and 160 AGeV and discuss their relation to model parameters describing the freeze-out process. We observe increasing HBT radii with decreasing impact parameter. This is consistent with the naive picture of a larger source at higher centrality.

^* Work supported in part by BMBF and GSI.