Evidence for the existence of the [2 0 2]3/2 deformed band in mirror nuclei 25Mg and 25Al.

After 50 years of its prediction, the highest-lying [2 0 2]3/2 orbit among the six Nilsson single-particle orbits originating from the sd shells in prolately deformed nuclei and the rotational band on this orbit were identified. The band members were observed in 2 5 Al at excitation energies of 6-7.5 MeV in a high-resolution 2 5 Mg( 3 He, t) charge-exchange reaction at 0° having a strong selectivity for Gamow-Teller transitions. In the comparison with the analogous Ml transitions in 2 5 Mg, the J π = 3/2 + bandhead state and the excited 5/2 + and 7/2 + members were clearly assigned.