Suppression of complete fusion due to breakup in the reactions $^{10,11}$B + $^{209}$Bi

TL;DR

This study investigates how breakup processes in weakly bound nuclei like $^{10,11}$B suppress complete fusion in reactions with $^{209}$Bi, revealing systematic suppression patterns related to breakup thresholds.

Contribution

It provides the first systematic analysis of complete fusion suppression due to breakup for $^{10,11}$B on $^{209}$Bi, quantifying suppression levels and their dependence on breakup thresholds.

Findings

CF cross sections are suppressed by 15% for $^{10}$B and 7% for $^{11}$B.

Fission predominantly originates from complete fusion.

Suppression of CF varies systematically with breakup threshold energy.

Abstract

Above-barrier cross sections of $\alpha$-active heavy reaction products, as well as fission, were measured for the reactions of $^{10,11}$B with $^{209}$Bi. Detailed analysis showed that the heavy products include components from incomplete fusion as well as complete fusion (CF), but fission originates almost exclusively from CF. Compared with fusion calculations without breakup, the CF cross sections are suppressed by 15% for $^{10}$B and 7% for $^{11}$B. A consistent and systematic variation of the suppression of CF for reactions of the weakly bound nuclei $^{6,7}$Li, $^{9}$Be, $^{10,11}$B on targets of $^{208}$Pb and $^{209}$Bi is found as a function of the breakup threshold energy.