Microscopic analysis of sub-barrier fusion enhancement in ${}^{132}$Sn+${}^{40}$Ca vs. ${}^{132}$Sn+${}^{48}$Ca}

Abstract

We provide a theoretical analysis of recently measured fusion cross sections which show a surprising enhancement at low $E_{c.m.}$ energies for the system ${}^{132}$Sn+${}^{40}$Ca as compared to the more neutron-rich system ${}^{132}$Sn+${}^{48}$Ca. Dynamic microscopic calculations are carried out on a three-dimensional lattice with a time-dependent density-constrained density functional theory. There are no adjustable parameters, the only input is the Skyrme effective NN interaction. Heavy-ion potentials $V(R)$, coordinate-dependent mass parameters $M(R)$, and total fusion cross sections $\sigma (E_{c.m.})$ are calculated for both systems. We are able to explain the measured fusion enhancement in terms of the {\it narrower width} of the ion-ion potential for ${}^{132}$Sn+${}^{40}$Ca, while the barrier heights and positions are approximately the same in both systems.

Comments: 5 pages, 5 figures. arXiv admin note: text overlap with arXiv:1201.5318