Narrow Results

Gerry Brown initiated some early studies on the coexistence of different nuclear shapes. The subject has continued to be of interest and is crucial for understanding nuclear fission. We now have a very good picture of the potential energy surface with respect to shape degrees of freedom in heavy nuclei, but the dynamics remain problematic. In contrast, the early studies on light nuclei were quite successful in describing the mixing between shapes. Perhaps a new approach in the spirit of the old calculations could better elucidate the character of the fission dynamics and explain phenomena that current theory does not model well.

The first excited state of the nucleus ²²⁹Th has an exceptionally small excitation energy of 7.8 eV, which is expected to be very sensitive to changes in the fine structure constant α. A small difference in the Coulomb energies of the two states, which both are of the order 10⁹ eV, would amplify variations in α into large variations of the transition frequency. Hartree-Fock and Hartree-Fock-Bogoliubov calculations are performed to compute the Coulomb energies of the two states. The kinetic energies are also calculated which reflect a possible variation in the nucleon or quark masses or local Lorentz invariance violation.