Nuclear energy density optimization: Large deformations

A new Skyrme-like energy density suitable for studies of strongly elongated nuclei was determined in the framework of the Hartree-Fock-Bogoliubov theory using the recently developed model-based, derivative-free optimization algorithm pounders. A sensitivity analysis at the optimal solution has revealed the importance of states at large deformations in driving the parameterization of the functional. The good agreement with experimental data on masses and separation energies, achieved with the previous parameterization unedf0, is largely preserved. In addition, the new energy density unedf1 gives a much improved description of the fission barriers in ${}^{240}$Pu and neighboring nuclei.