This title appears in the Scientific Report :
2005
Please use the identifier:
http://hdl.handle.net/2128/419 in citations.
K$^{+}$ -Meson Production in Nuclei
K$^{+}$ -Meson Production in Nuclei
This report summarises the results of the physics programme, performed in the years 1998–2003, which became possible after taking into operation the ANKE spectrometer at an internal target position of the accelerator facility COSY-Jülich. Primary goal when building ANKE was to provide a tool which a...
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Personal Name(s): | Büscher, Markus (Corresponding author) |
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Contributing Institute: |
Institut 2 (Experimentelle Kernphysik II); IKP-E-2 |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2005
|
Physical Description: |
1 CD-ROM |
Dissertation Note: |
Universität Köln, Habil., 2005 |
ISBN: |
3-89336-398-X |
Document Type: |
Habil / Postdoctoral Thesis (Non-german Habil) |
Research Program: |
Physik der Hadronen |
Series Title: |
Schriften des Forschungszentrums Jülich. Reihe Materie und Amterial / Matter and Materials
29 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
This report summarises the results of the physics programme, performed in the years 1998–2003, which became possible after taking into operation the ANKE spectrometer at an internal target position of the accelerator facility COSY-Jülich. Primary goal when building ANKE was to provide a tool which allows one to study processes leading to K$^{+}$-meson production in interactions of protons with atomic nuclei, in particular at beam energies far below the free nucleon-nucleon threshold. From such data one hopes to extract information about the influence of the nuclear medium on elementary K$^{+}$-production processes (i.e. in free proton-proton interactions), about the in-medium properties of this meson, and about collective effects in nuclear matter. The construction of ANKE and the K+-detection systems was started in 1989. After the integration of ANKE into the COSY accelerator ring in 1998, inclusive K$^{+}$-momentum spectra were measured in a first series of experiments (p+A $\rightarrow$ K$^{+}$X for different target nuclei A=C, Cu, Ag, Au). These data reveal a high degree of collectivity in the target nuclei and, for the first time, allow one to extract the nuclear potential (or “in-medium mass”) of K$^{+}$ mesons at normal nuclear density with high accuracy. The ANKE data on K$^{+}$ production in proton-deuteron interactions indicate a large production cross section on neutrons, as compared to proton targets. This fact must be taken into account, e.g., for the theoretical description of heavy ion data. In the second phase of the experimental program, K$^{+}$ mesons from protoncarbon interactions were measured in coincidence with protons and deuterons (p+C $\rightarrow$ K$^{+}$ (p or d)X). These novel data yield information about the kaon production mechanisms and give evidence for cluster-formation processes. Corresponding coincidence data for proton-proton collisions (p+p $\rightarrow$ K$^{+}$ $\overline{K}^{0}$ d) revealed that K $\overline{K}$-pair production close to threshold is dominated by kaons produced in a relative S-wave. This has been interpreted in terms of the first observation of scalar meson (a$^{+}_{0}$) production at COSY. The realisation of ANKE and the experiments has been made possible by the combined efforts of a large number of people, in particular my colleagues and friends from the ANKE collaboration. I want to express my deep gratitude for a successful and (mostly) enjoyable collaboration. I am particularly appreciative for support by the former director and director of IKP-II, Profs. O. Schult and H. Ströher, and my Ph.D. advisor and predecessor as ANKE spokesperson, Prof. K. Sistemich. This work profited especially from a close collaboration with Prof. L. Kondratyuk, Dr. V. Koptev (“the Master of all Kaons”), Dr. A. Sibirtsev as well as the former Ph.D. students, Dr. A. Franzen and Dr. V. Kleber (who generously tolerated being classified as “servants”). Section 3 gives a brief introduction into the properties of ANKE and the K$^{+}$- detection systems. The main experimental results and their interpretation are outlined. Further details can be found in the attached publications. The author has been the spokesperson of the international ANKE collaboration, which currently comprises $\sim$ 120 researchers, since 1999. |