Unraveling the reaction mechanism for large alpha production and incomplete fusion in reactions involving weakly bound stable nuclei

The origin of the large alpha particle production and incomplete fusion in reactions involving weakly bound alpha+x cluster nuclei still remains unresolved. While the (two-step) process of breakup followed by capture of the free complementary fragment (x) is widely believed to be responsible, a few recent studies suggest the dominant role of (direct) cluster stripping. To achieve an unambiguous experimental discrimination between these two processes, a coincidence measurement between the outgoing alpha particles and gamma rays from the heavy residues has been performed for the Li-7(alpha+triton)+Nb-93 system. Proper choice of kinematical conditions allowed for the first time a significant population of the region accessible only to the direct triton stripping process and not to breakup followed by the capture of the free triton (from the three-body continuum). This result, also supported by a cluster-transfer calculation, clearly establishes the dominance of the direct cluster-stripping mechanism in the large alpha production. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

The study investigates the origin of large alpha particle production and incomplete fusion in reactions involving weakly bound alpha+x cluster nuclei. By measuring the correlation between outgoing alpha particles and gamma rays from heavy residues in the Li-7(alpha+triton)+Nb-93 system, it was found that the direct cluster-stripping mechanism plays a dominant role in large alpha production.