Identification of the [202]3/2 deformed band in mirror nuclei Mg-25 and Al-25 and implications for unstable nuclei

Fifty years after its prediction, the highest-lying [ 2 0 2] 3) 2 orbit among the six Nilsson single-particle orbits originating from the sd shell in prolately deformed nuclei and the rotational band on this orbit were identified. The band members were observed in Al-25 at excitation energies of 6-7.5MeV in a high-resolution Mg-25(He-3,t) charge-exchange reaction at 0 degrees having a strong selectivity for Gamow-Teller transitions. In comparison with the analogous M1 transitions in Mg-25, the J(pi) = 3/+ band-head state and the excited 5/+ and 7/2+ members were clearly assigned.