Research Abstract |
In the mass region around 130, interesting phenomena are found such as high-spin isomers, backbending phenomena, triaxial deformation, chiral bands. Moreover, these nuclei provide necessary information concerning the abundance of species which are made in supernovae explosions. The nuclei treated in this research are neither vibrational nor rotational nuclei, thus cannot be described in terms of mean field theories. We describe them in terms of the pair-truncated model which assumes angular momentum 0 and 2 collective pairs. In ^<132>Ba we have successfully reproduced ground state band, quasi-gamma band, and states in backbending region. The backbending is confirmed to be caused by the alignment of neutrons due to the magnetic dipole moment of 10^+ state. The similar study has been done for Xe isotopes, predicting the 10+ isomer just above the 8^+ state. In ^<132>La, the chiral band is predicted theoretically. However, we have predicted that two angular momenta by neutrons and protons are rather parallel than orthogonal. As a preliminary calculation, we have shown that our model has a predictive power for the beta decays as well.
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