Proton backbend in the doubly-magic superdeformed nucleusGd144

A discrete superdeformed rotational band has been discovered in [sup 144]Gd following the reaction [sup 100]Mo([sup 48]Ti, 4[ital n])[sup 144]Gd at 221 MeV. The dynamical moment of inertia shows a sharp irregularity at [h bar][omega]=0.45 MeV. The intensity of the [gamma]-ray transitions suggests that the irregularity can be associated with a backbend, which is interpreted in terms of the [ital N]=6 proton band crossing. The experimental results are in good agreement with cranked mean field calculations, which indicate the presence of large shell gaps for both protons and neutrons.