Speaker
Description
We discuss the role of two-neutron transfer processes in the fusion reaction of the $^{9,11}$Li + $^{208}$Pb systems.
We first analyze the $^{9}$Li + $^{208}$Pb reaction by taking into account the coupling to the
$^{7}$Li + $^{210}$Pb channel. To this end, we assume that two neutrons are directly transferred to a single effective channel in $^{210}$Pb and solve the coupled-channels equations with \textcolor[rgb]{0.98,0.00,0.00}{the} two channels. By adjusting the coupling strength and the effective $Q$-value, we successfully reproduce the experimental fusion
cross sections for this system. We then analyze the $^{11}$Li + $^{208}$Pb reaction in a similar manner, that is, by taking into account three effective channels with
$^{11}$Li + $^{208}$Pb, $^{9}$Li + $^{210}$Pb, and $^{7}$Li + $^{212}$Pb
partitions. In order to take into account the halo structure of the $^{11}$Li nucleus,
we construct the potential between $^{11}$Li and $^{208}$Pb with a double folding procedure, while we employ a Wood-Saxon type potential with the global Aky\"uz-Winther parameters for the other channels.
Our calculation indicates that the multiple two-neutron transfer process plays a crucial role in the $^{11}$Li + $^{208}$Pb fusion reaction at energies around the Coulomb barrier.
