Spectroscopy of positive parity states in Mg26 and Al26 via the (3He) and (,t) reactions

The (,3He) and (,t) reactions on Mg25 were measured at E=50 MeV. Cross sections obtained for 57 positive parity states in Mg26 and Al26 were analyzed within the framework of the exact-finite-range distorted-wave Born approximation and compared to the full s-d shell model predictions. Reasonable agreement between the experimental strengths and the theory was obtained for the low lying states. Deviations of factors of 2 or more were found for some high lying 2+, 3+, and 4+ states in Al26 and especially for the 11+ state in Mg26. The spectroscopic factors for the transitions to the analog states in Mg26 and Al26 were compared between these reactions. The same strength was obtained for the 61-, T=1 state in Mg26 and Al26, whereas an enhancement of about 30% was observed for the 01+ and 31+, T=1 states in Al26. Further, 1+ states in Mg26 proposed around Ex=10 MeV through the (p,p) reaction were also observed in the Mg25(,3He) reaction without the special enhancement for the 10.6 MeV 1+ state seen in the (p,p) reaction. The total observed strengths for neutron stripping to the positive-parity states in the region of Ex=011 MeV almost attained the limit of the pure j-j coupling scheme. Those for the proton stripping were 70% of the limit in the region of Ex=08 MeV.