Investigation of 3/2${}_2^{-}$ state of ${}^9$Li nucleus with microscopic structure and reaction models

Abstract

The low-lying states of the ${}^9$Li nucleus are investigated with a unified framework of microscopic structure and reaction models. In the structure model, the wave function is fully antisymmetrized and the ${}^9$Li nucleus is described as an $\alpha$ + $t$ + $n$ + $n$ four-body system, and low-lying 1/2${}^{-}$, 3/2${}^{-}$, 5/2${}^{-}$, and 7/2${}^{-}$ states are obtained by the stochastic multi-configuration mixing method. Using these wave functions, the quasi-elastic cross section at $E/A$ = 60 MeV and the elastic and inelastic cross sections at $E/A$ = 50 MeV on the ${}^{12}$C target are calculated in the framework of the microscopic coupled channel (MCC) method. The characteristic inelastic angular distribution is seen in the 3/2${}_2^{-}$ state, whose $\alpha +t$ cluster structure and valence neutron configurations are discussed in detail. We find the possibility of triaxial deformation and mixing of di-neutron components in the ${}^9$Li nucleus.

Comments: 10 pages, 11 figures, 5 tables