Coupled-channels analyses for 9,11Li + 208Pb fusion reactions with multi-neutron transfer couplings

Abstract

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 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 Akyüz-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. 25.70.Jj

Sub-barrier fusion reactions

“…At the same time, it may also enhance fusion cross sections if couplings to a breakup channel dynamically lowers the Coulomb barrier [48,49,50], 3. the transfer processes. Since the Q-value is positive for neutron-rich nuclei, it may significantly affect the fusion process [51,52].…”

Fusion reaction of a weakly bound nucleus with a deformed target

“…In order to investigate a possible origin for the discrepancy, we follow Ref. [18] and consider a transfer coupling to the 14 C + 233 Th channel. That is, we consider a transfer to a single effective channel [38] and solve the coupled-channels equations [22,31] of…”

“…Fusion reactions of halo nuclei have attracted lots of attention [9][10][11][12][13][14][15][16][17][18][19]. It is generally known that fusion cross sections at energies around the Coulomb barrier are sensitive to the structure of colliding nuclei [20][21][22][23][24], and it is thus likely that the halo structure significantly affects fusion reactions, in both static and dynamical ways.…”

Semi-classical approaches to heavy-ion reactions: fusion, rainbow, and glory

“…-The transfer processes. For neutron-rich nuclei, a transfer Q-value is likely positive, which may significantly influence fusion reactions [37]. It is still a challenge to take into account simultaneously both the transfer and the breakup processes in a theoretical calculation [38].…”