Nuclear Physics Seminar

We demonstrate that hot superheavy nuclei do not retain spherical shapes, as traditionally assumed, but instead equilibrate in deformed —often oblate or triaxial— configurations at finite excitation energy. This behavior arises from a mechanism analogous to the Jahn--Teller effect: spherical systems exhibit high single-particle degeneracy near the Fermi surface, causing their shell corrections to damp out significantly faster with temperature than those of deformed shapes. Using a finite-temperature framework, we reveal a thermally induced inversion of the potential-energy landscape in the Z=118-120 region, where deformed minima become energetically favored at U ~= 30-50 MeV. This shape inversion fundamentally alters the competition between neutron evaporation and fission. We derive a deformation-dependent correction to the survival probability, revealing a systematic bias in estimates based on spherical ground-state properties. Our results identify a finite-temperature structure effect that calls for a revision of current models of superheavy nucleus synthesis and decay.