THE STRUCTURE OF NEUTRON-RICH 28,29Mg STUDIED THROUGH β-DECAY OF SPIN POLARIZED 28,29Na BEAMS AT TRIUMF

The level structures of 28Mg and 29Mg have been investigated by the β-decay of spin-polarized28Na and 29Na at ISAC, TRIUMF. The detailed β-γ and γ-γ coincidence measurements were performed. New γ rays and β transitions were observed both in 28Mg and 29Mg. We have succeeded in assigning spins and parities of many levels in 28Mg and 29Mg. Comparison with shell model calculations using USD Hamiltonian suggest that the structure of 28Mg and 29Mg are well explained in the sd-shell configurations, except for two levels at 1.095 and 1.430 MeV in 29Mg. This suggests negative parity assignments for these levels. The evolution of sd-pf shell is discussed.