Semi-microscopic modeling of heavy-ion fusion reactions with multi-reference covariant density functional theory

Abstract

We describe low-lying collective excitations of atomic nuclei with the multi-reference covariant density functional theory, and combine them with coupled-channels calculations for heavy-ion fusion reactions at energies around the Coulomb barrier. To this end, we use the calculated transition strengths among several collective states as inputs to the coupled-channels calculations. This approach provides a natural way to describe anharmonic multi-phonon excitations as well as a deviation of rotational excitations from a simple rigid rotor. We apply this method to subbarrier fusion reactions of ${}^{58}$Ni+${}^{58}$Ni, ${}^{58}$Ni+${}^{60}$Ni and ${}^{40}$Ca+${}^{58}$Ni systems. We find that the effect of anharmonicity tends to smear the fusion barrier distributions, better reproducing the experimental data compared to the calculations in the harmonic oscillator limit.

Comments: 11 pages, 9 eps figures