Statistical Theory of Nuclear Reaction

Using novel method of generating function Grassmann integral developed by Weidenmiiller's group westudied the statistical theory of nuclear reactions and相关问题obtain results to becompared with experimental data. For equilibrium compound process直接互动的影响包括Nishioka - Weidenmuller transformation的inverse。effects are mainly contained in The transmission matrix. Is studying decay of giant resonancestransmission matrix是calculated，这是用来衡量直接互动效果在多步骤共同进程中的情况optical potential whose absorption imaginary part is limited to bound configuration must beused.In studying nuclear reactions partial level densities (PLD) are必要性. Includingindependent particle model spectra and random residual in action we have been continuing work onPLD. To be realistic spin parity assignment is now included. By neglecting Pauli - principleconsistently we wleto calculate PLD with reasonable computing time without spoiling theaccuracy. Experimental data high spin states of ^<208>Pb by inelastic scattering of proton wasexplained fairly well by our PLD.By using简单模型the multistep compound reaction crosssections are evaluated neglecting direct reaction effects for <40>Ca and ^<280>Pb. Both strong andweak couplings assumed. In strong coupling case the reaction proceeds to high excitation stateswith less neutron emission compared with the weak coupling case. For <280>Pb fluctuation crosssection is found to vanish in the weak coupling limit because of lack of levels in these energyregions. So far out study is limited to closed shell nuclei，但我们希望extend to open shell spherical nuclei by introducing pairing correlation。

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.