München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 39: Physik mit schweren Ionen

HK 39.5: Vortrag

Mittwoch, 22. März 2006, 18:00–18:15, D

Production of K_S⁰ and Λ at High Transverse Momentum in Pb+Pb collisions at 158A GeV^* — •T. Schuster¹, C. Alt¹, C. Blume¹, P. Dinkelaker¹, D. Flierl¹, V. Friese², M. Gaździcki¹, C. Höhne², M. Kliemant¹, S. Kniege¹, B. Lungwitz¹, M. Mitrovski¹, M. Otto¹, R. Renfordt¹, A. Sandoval², R. Stock¹, C. Strabel¹, and H. Ströbele¹ — ¹Institut für Kernphysik, Universität Frankfurt — ²Gesellschaft für Schwerionenforschung (GSI), Darmstadt

In ultrarelativistic heavy ion collisions, the bulk of the particles is produced in the transverse momentum region of p_t < 2 GeV/c. However, important information about the produced matter can be obtained from the higher p_t domain. Properties of the baryon/meson ratios and the elliptic flow in the region 2 < p_t < 4 GeV/c seen at RHIC can be explained by quark coalescence models. A study of the p_t dependence of baryon/meson ratios at the top SPS energy can answer the question which hadron production mechanisms are relevant in this energy range.

In the NA49 large acceptance hadron spectrometer, K_S⁰ and Λ are identified via the V⁰ topology of their decay into charged hadrons and the determination of their invariant mass. The available data allows for particle identification up to p_t = 3.8 GeV/c (K_S⁰) and p_t = 4.4 GeV/c (Λ).

Preliminary spectra of K_S⁰ and Λ at high p_t produced in central Pb+Pb reactions at 158A GeV will be presented. The Λ / K_S⁰ ratio will be compared to models and to data obtained at RHIC.

^* Supported by BMBF and GSI