Probing the shape of hot 194Hg at high spins with the giant dipole resonance decay in selected cascades -: art. no. 014306

High-energy gamma rays emitted by the decay of the hot compound nucleus Hg-194, formed in the reaction Si-30(142 MeV)+ Dy-164, have been measured in coincidence with different residual nuclei. The measured spectra and the relative residual-nucleus cross sections were simultaneously analyzed with the statistical model. Calculations assuming contributions from a GDR in superdeformed states were also made. No clear evidence was found that superdeformed shapes seen at T = 0 survive at average nuclear temperature [T] similar or equal to 1.3 MeV. Instead, an average nuclear deformation corresponding to [beta] = 0.3 constant with spin has been deduced for 20<I<38 h by comparing the measured width to that predicted by the model of thermal shape fluctuations.