Bonn 2010 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
HK: Fachverband Physik der Hadronen und Kerne
HK 5: Hadronenstruktur und -spektroskopie II
HK 5.7: Talk
Monday, March 15, 2010, 18:00–18:15, HG IV
Systematic study of the reactions pp→ pK+Λ and pp→ pK+Σ0 at moderate excess energies — •Martin Schulte-Wissermann1, Hartwig Freiesleben1, Wolfgang Ullrich1, and Kai-Thomas Brinkmann2 — 1Institut für Kern- und Teilchenphysik, Technische Universität Dresden — 2HISKP, Universität Bonn
The time-of-flight spectrometer COSY-TOF installed at COSY, Forschungszentrum Jülich, stands out for its large geometric acceptance. With this detector the dynamics of a great variety of reaction channels can be studied, as both total and differential cross sections are accessible. In this talk, we present results of the simultaneously measured reactions pp→ pK+Λ and pp→ pK+Σ0 at excess energies of 204, 239, and 284 MeV (Λ) and 127, 162, and 207 MeV (Σ0). It is concluded from the total cross sections that the high energy limit of the Λ to Σ0 cross section ratio is already reached at an excess energy of only 200 MeV. From the differential distributions observed in the overall CMS, the Jackson, and helicity frames, a significant contribution of nucleon resonances to the Λ-production mechanism is deduced. The differential distributions for the Σ0-channel, measured for the first time, indicate a significant contribution of kaon exchange to the production mechanism. The data clearly show the strangeness production mechanisms to be distinctively different for these two hyperon channels. The data provide a benchmark of high quality for theoretical models already available or yet to come. (Supported by BMBF and FZ Jülich)