1990 Fiscal Year Final Research Report Summary
Statistical Theory of Nuclear Reaction
| Project/Area Number |
63540204
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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 | Ishinomaki Senshu University (1989-1990)
Yamagata University (1988) |
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Principal Investigator |
YOSHIDA Shiro Ishinomaki Senshu U. Fac. of Science and Technology Prof, 理工学部, 教授 (60091766)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Yoshio Yamagata U. Fac. General Edc. Associate Prof, 教養部, 助教授 (10113961)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Nuclear reaction / Statistical theory of nuclear reaction / Multistep compound process / Partial level density / Level density / Decay of giant resonance |
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| Research Abstract |
Using novel method of generating function Grassmann integral developed by Weidenmiiller's group we studied the statistical theory of nuclear reactions and related problems to obtain results to be compared with experimental data. For equilibrium compound process, effects of direct interaction are included by the inverse of NishiokaーWeidenmuller transformation. The effects are mainly contained in the transmission matrix. Is studying decay of giant resonances the transmission matrix is calculated, which is used to evaluate the direct interaction effects on multistep compound process. In this case the imaginary part of optical potential whose absorption is limited to bound configuration must be used.
In studying nuclear reactions partial level densities (PLD) are necessary. Including independent particle model spectra and random residual in reaction we have been continuing work on PLD. To be realistic spin parity assignment is now included. By neglecting Pauliーprinciple consistently we were ableto calculate PLD with reasonable computing time without spoiling the accuracy. Experimental data high spin states of ^<208>Pb by inelastic scattering of proton was explained fairly well by our PLD.
By using simple model the multistep compound reaction cross sections are evaluated neglecting direct reaction effects for ^<40>Ca and ^<280>Pb. Both strong and weak couplings are assumed. In strong coupling case the reaction proceeds to high excitation states with less neutron emission compared with the weak coupling case. For ^<280>Pb fluctuation cross section is found to vanish in the weak coupling limit because of lack of levels in these energy regions. So far out study is limited to closed shell nuclei, but we hope to extend to open shell spherical nuclei by introducing pairing correlation.
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Research Products
(12 results)
