Sensitivity of fission barrier heights to nuclear matter properties

Abstract

We systematically investigate the correlations between nuclear fission properties and the surface energy coefficient $a_{\rm surf}$ extracted from semi-infinite nuclear matter. To this end, we employ the covariant density functional theory based on a point-coupling energy density functional (EDF). Taking $^{240}$Pu and $^{236}$U as representative examples, we employ Gaussian-process emulators to construct the joint posterior distributions of $a_{\rm surf}$ and selected fission observables, constrained by the ground state properties of the two nuclei. The results reveal a strong correlation between $a_{\rm surf}$ and the fission barrier heights. A sensitivity analysis further shows that the height of the outer fission barrier is governed predominantly by the isoscalar-vector derivative coupling constant $δ_V$ in the point-coupling EDF, whereas that of the inner barrier is by the combined effects of $δ_V$ and several mutually correlated coupling constants.