1991 Fiscal Year Final Research Report Summary
Analyses of Hypernuclear Production and Pionic Decay Reactions
| Project/Area Number |
01540254
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Osaka Electro-Communication University |
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Principal Investigator |
MOTOBA Toshio Osaka Electro-Communication University, Laboratory of Physics, Professor, 工学部, 教授 (90121863)
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| Co-Investigator(Kenkyū-buntansha) |
ITONAGA Kazunori Miyazaki Medical College, Laboratory of Physics, Professor, 教授 (90029546)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Hypernucleus / Polarization / kaon Induced Reaction / Pion Induced Reaction / Kaon Photoproduction / Pionic Decay / Weak Interaction / Strangeness |
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| Research Abstract |
The extensive theoretical analyses have been performed for the hypernuclear production by all the (K^-, pi^-), (pe^+, K^+) and (gamma, K^+) reactions on the p-shell nuclear targets. We use the reliable hypernuclear wave functions obtained in the extended Cohen-Kurath type calculations. The second improvement in the theoretical treatment has been exploited by starting with the elementary amplitudes including the spin-flip component. The existing reaction data are successfully explained by our model with new framework. Furthermore we can predict not only various reaction cross sections but also the polarization abilities of the three reactions. The characteristics of these processes are clarified to be very useful in future hypernuclear spectroscopy.
The pionic weak decay rates are systematically evaluated for wide region of hypernuclei : s-shell, p-shell, sd-shell and typical heavy systems up to the lead region. The full form of pion-nucleus optical potential is employed with the consistent vertex renormalization. Thus we present the standard theoretical estimates of pionic decays for light-to heavy hypernuclei. For heavy systems, we discussed an interesting interplay between the Pauli blocking and the restoration due to pion distortion as a function of mass number. For p-shell and sd-shell region, we emphasized a remarkable shell-structure dependence which should be useful in the detailed analysis. For very light LAMBDA- and LAMBDA LAMBDA-hypernuclei, the continuum pion spectra for the three-body unbound final states are calculated in the frame work of Kapur-Peierls method. The comparison with existing data are satisfactory.
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