Evidence of compound nucleus theory in the population of incompletely fused composite system ^160 Dy*

The fusion excitation functions of evaporation residues, populated through complete fusion and/or incomplete fusion, were measured in the ^18 O+ ^146 Nd system at an incident beam energy of ≈ 3–7 MeV/nucleon. These results were then compared with those obtained from the previously reported ^16 O+ ^148 Nd system. This comparison is particularly relevant since both systems lead to the population of the same compound nucleus, ^164 Er*, in the case of complete fusion, and the same intermediate composite system, ^160 Dy*, in the case of incomplete fusion. Significant enhancements in the measured excitation functions of evaporation residues populated via α -emitting channels indicate the population of such residues via incomplete fusion in addition to complete fusion. Further, a comparison of the measured data for ^18 O+ ^146 Nd and ^16 O+ ^148 Nd systems shows interesting results. The complete fusion and incomplete fusion cross-sections, reduced by three different procedures, are found to satisfactorily match each other, despite the major difference in the α - breakup threshold values of the projectiles ^18 O (6.23 MeV) and ^16 O (7.16 MeV). The effect of different α -breakup threshold values of the projectiles ^18 O and ^16 O was not observed in the comparison of incomplete fusion data for the systems ^18 O+ ^146 Nd and ^16 O+ ^148 Nd. This may be attributed to the fact that the residues populated in the exit channel are emitted from the same intermediate composite system ^160 Dy* and also there is a high resemblance in the entrance channel mass asymmetry and other structural properties of these systems.