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.

Biography

Prof. Michał Kowal is a theoretical physicist. His scientific interests include the prediction of cross-sections (synthesis probabilities) for existing and planned super-heavy nuclei, as well as stability analysis, including the calculation of lifetimes for the heaviest nuclei. He obtained his Master’s degree and Ph.D. in Physics from Maria Curie-Sklodowska University in 1999 and 2004, respectively. He is currently a professor and the head of the Department of Theoretical Physics at the National Centre for Nuclear Research, Poland.

Inviter: Shan-Gui Zhou