Study of Preequilibrium Process by Sudden Approximation
Project/Area Number  04640309 
Research Category 
GrantinAid for Scientific Research (C).

Research Field 
核・宇宙線・素粒子

Research Institution  Ishinomaki Senshuu University 
Principal Investigator 
YOSHIDA Shiro Ishinomaki Senshuu University, Faculty of Science and Thechnology, Professor, 理工学部, 教授 (60091766)

CoInvestigator(Kenkyūbuntansha) 
TAKAHASHI Yoshio Yamagata University, Faculty of General Education, Professor, 教養部, 教授 (10113961)
ABE Masanori Ishinomaki Senshuu University, Faculty of Science and Thechnology, Lecturer, 理工学部, 講師 (50221049)

Project Fiscal Year 
1992 – 1994

Project Status 
Completed(Fiscal Year 1994)

Budget Amount *help 
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1994 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1993 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1992 : ¥1,200,000 (Direct Cost : ¥1,200,000)

Keywords  Preequllibrium process / Absorptive Potential / Statistical Theory of Nuclear Reaction / Dynamical Shell Model / Semiclassical Approximation / 前平衡過程 / 光学ポテンシャルの虚部 / 核反応の統計理論 / 動的殻模型 / 半古典近似 / 断熱近似 
Research Abstract 
Preequilibrium multistep compound process is described by the master equation, which is derived under the statistical assumption. Parameters appeared there are obtained from an absorptive potential with fixed exction number. The potential is calculated by using the deltainteraction and furthermore the transmission coefficients are obtained. From which stage of the multistep direct process the multistep compound process starts had been a question. We calculated contributions from the first stage and the second stage and both are found to be equally important. This agrees with conclusions from phenomenological analyzes. However the Pauli blocking effect are not taken into account in the absorptive potentials. As a temperature fixed state is a mixture of various exciton states, the absorptive potential with fixed temperature is decomposed into ones for various exciton states, and absorptive potential for preequilibrium processes are obtained Under the Fermi liquid approximation the calculation is analytically performed. On the other hand the numerical calculations with delta interaction is also performed, and both results are compared. When intermediates states are limited to bound configurations like in the case of preequilibrium process, agreements become worse as the incident energy increases, while if the intermediate states are not restricted agreements are pretty good. In this calculation the effect of Pauli blocking is taken into account. Transition probabilities between exciton states are obtained by the second moment of the interaction if the matrix elements are random. The second moments are obtained from the spreading width, which is calculated from the absorptive potential. If the semiclassical approximation is adopted then the spreading widths are obtained as a function of energy for a fixed spinparity state. These results are useful for studies of preequilibrium as well as the dynamical shell model.

Report
(5results)
Research Output
(17results)