2007 Fiscal Year Final Research Report Summary
Semiclassical distorted wave model analyses of meson production spectra and medium modifications of elementary processes
| Project/Area Number |
17540263
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Kyushu Dental College |
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Principal Investigator |
KOHNO Michio Kyushu Dental College, Dentistry, Professor (40234710)
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| Project Period (FY) |
2005 – 2007
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| Keywords | hadron physics / semiclassical distorted wave model / inclusive spectra / Σ hyperon / Ξ hyperon / hyperon-nucleon interaction / η meson / eauivalent interaction |
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| Research Abstract |
It is an important subject to investigate how various baryons behave in nuclear medium. Various models of baryons and their excited states are to be checked by observing meson production spectra on nuclei To analyze the experimental spectra, however it is necessary to use realistic wave functions for hadrons in incident and final states, decent treatments of the Fermi motion of target nuclear wave functions, the transition to the two-body center of mass frame from the incident particle-nucleus system, proper accounts of the energy and omentum dependences of the relevant elementary processes. In addition we have to be aware of the possible modification of the hadron properties in nuclear medium.
We have developed, in this study, the semiclassical distorted wave model description for the meson production inclusive spectra on nuclei, in which calculational complexities are lessened by introducing the semi-classical approximation for the propagation of the interacting particles, but preserv
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e the energy and angle dependences of the elementary amplitudes. Thus we can avoid the frequently used Fermi-averaging approximation. We applied our method first to (π^-, K^+)Σ^- formation inclusive spectra and established that the Σ hyperon feels repulsion of the order of several tens MeV. This finding constrains the theoretical construction of the hyperon-nucleon two-body potential model. Next, we considered the (K, K^+)Ξ^- formation inclusive spectra. The existing data is not accurate enough to discuss the Ξ nucleus potential, but the situation will change in near future. The photo-production cross section of the γmeson was also considered in our method, in which in-medium properties of the Su resonance are studied through the dominant coupling of the γN to this nucleon resonance.
We need some effective interaction theory to relate the two-body hyperon-nucleus interaction and the hyperon-nucleus potential. We applied the low-momentum space equivalent interaction theory to the hyperon-nucleon interaction and clarified the basic properties of the existing models of the YN interaction based on the meson-exchange picture as well as the quark picture. Less
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Research Products
(22 results)
