Oblate deformed shapes of hot rotating nuclei deduced from giant-dipole-resonance decay studies

Abstract

The spectrum shape and the angular distribution of \ensuremath{\gamma} rays from highly excited and rotating $^{90}\mathrm{Zr}$ and $^{92}\mathrm{Mo}$ compound nuclei were measured and analyzed. The results are in good agreement with theory including both intrinsic-shape fluctuations and shape-orientation fluctuations about an equilibrium shape which changes from spherical to oblate deformed with increasing spin.