Breakup and Incomplete Fusion Mechanisms of 7Be + 208Pb Reactions*

Weakly-bound nuclei (e.g. $^{6,7}$Li, $^9$Be) are observed to have up to 35\% suppression of complete fusion compared to single-barrier penetration models when reacting with heavy targets at above-barrier energies [1] [2].

This complete fusion suppression is associated with substantial yields of incomplete fusion, where only part of the projectile is captured. This phenomenon is known to be more complicated than simple projectile breakup [3][4][5].

The yields and characteristic breakup timescales cannot explain the degree of fusion suppression [6][7][8].

Instead, an additional mechanism of direct cluster transfer has been suggested, consistent with analysis of the alpha-particle leftover after incomplete fusion [3]. These reaction dynamics depend strongly on the cluster structure and degree of weak-binding and become further complicated away from stability, as valence nucleons become more weakly bound. Therefore, to investigate breakup dynamics away from stability, we measured the breakup, complete and incomplete fusion of $^7$Be, the mirror-nucleus of $^7$Li, on $^{208}$Pb at above-barrier energies. By comparing the breakup of $^7$Be and $^7$Li, we aim to disentangle the competing effects of low-lying structure with binding. The ongoing analysis of the $^7$Be breakup data will be discussed.