Український математичний конгрес - 2009
Юлия Дубровская (Одесский государственный университет ОГЭКУ, Одесса, Украина)
Generalized multiconfiguration model of decay of the multipole giant nuclear resonances
It’s known that an account of complex configurations has significant meaning for adequate explanation of the widths, structure and decay properties of the multipole giant nuclear resonances (MGR). Here we present generalized multiconfiguration model to describe a decay of high-excited states, which is based on the mutual using the shell models (with limited basis) and microscopic model of pre-equilibrium decay with statistical account for complex configurations 2p2h, 3p3h etc in some analogy with the Zhivopistsev-Slivnov model 9see e.g. ). All possible configurations are divided on two grops: i) group of complicated configurations “n1”, which must be considered within shell model with account for residual interaction; ii) statistical group “n2” of complex configurations with large state denstiy p(n,E)>> and strong overlapping the states Gn>>Dn-1>Dn (Dn is an averaged distance between states with 2n exciton; Gn is an averaged width). To take into account a collectivity of separated complex configurations for input state a diagonalization of residual interaction on the increased basis (ph,ph+phonon, ph+2 phonon) is used. Giant resonance is treated on the basis of the multi-body shell model initial wave functions of MGR for nuclei with closed or almost closed shells are found from diagonalization of residual interaction on the effective 1p1h basis . Process of arising a collective state of MGR and an emission process of nucleons are described by corresponding diagram with V effective Hamiltonian of interaction, resulted in capture of muon by nucleus with transformation of proton to neutron and emission by antineutrino. Isobaric analogs of isospin & spin-isospin resonances of finite nucleus are excited. Proposed model of decay of the multipole giant resonances is applied to analysis of some important nuclear reactions .