Three-body analysis of ~(11)Be~* Li and its β-decay to deuteron channel and to halo analog state ~(11)Be (18.3 MeV)

摘要

The ground state wave function of ~(11)Li obtained in a three-body model proposed earlier (S Kumar and V S Bhasin, Phys. Rev. C65, 034007 (2002)) has been employed to study the probability distributions, momentum distributions and n-n correlation. Complex scaling method has been used to find the energy positions and widths of the three resonant states of ~(11)Li above the breakup threshold. The formalism is extended further to study the β-decay of ~(11)Li to two channels. One is the β-transition of ~(11)Li into a high lying excited state of ~(11)Be at 18.3 MeV, i.e., ~(11)Be~* and the second is the decay to deuteron + ~9Li channel, The ~(11)Be~* state has been considered as a halo analog state identified as a bound three-body (~9Li + n + p) system. The n- ~9Li interaction incorporates both the virtual state and the p-wave resonance observed experimentally. For p- ~9Li interaction, a Coulomb corrected separable interaction is constructed using charge iudepedendence for strong interaction part. The n-p interaction is operative only in ~3S_1 state corresponding to the isotopic spin T_h = 0. As a result the ~(11)Be~* state has the same isotopic spin as that of ~9Li core, i.e., T = 3/2. Using these realistic parameters as input and without invoking any other free parameter, the model has been used to predict the strength of the Gamow-Teller β-decay of ~(11)Li to ~(11)Be~*, i.e., B_(GT) = 1.5 and the value of the branching ratio to ~9Li + deuteron channel to be 1.3 x 10~(-4). These results are found to be in rather good agreement with the recent experimental findings.