Disentangling fractional momentum transfer in the F19+Sm154 system

Forward recoil range distributions of evaporation residues produced in the system $^{19}\mathrm{F}+^{154}\mathrm{Sm}$ were measured at projectile energy $\ensuremath{\approx}107$ MeV using the offline $\ensuremath{\gamma}$-ray activation technique. The entire and fractional linear momentum transfers inferred from these recoil range distributions were used to identify the evaporation residues formed by complete and incomplete fusion mechanisms. The forward recoil range distributions of measured evaporation residues populated through $x\mathrm{n}/\mathrm{p}x\mathrm{n}$ channels were found to be consisting of a single peak only while the evaporation residues populated through $\ensuremath{\alpha}$ emitting channel had contributions from incomplete fusion also. The observed incomplete fusion process in the population of $\ensuremath{\alpha}$ emitting channel residues is explained through the breakup fusion model. The results indicate the occurrence of incomplete fusion involving the breakup of $^{19}\mathrm{F}$ into $^{4}\mathrm{He}+^{15}\mathrm{N}$ and/or $^{8}\mathrm{Be}+^{11}\mathrm{B}$ followed by fusion of one of the fragments with target nucleus $^{154}\mathrm{Sm}$. From these measurements, the relative contributions of complete and incomplete fusion were separated out. The forward recoil range distributions data show that the incomplete fusion contribution in the fusion of fragment $^{15}\mathrm{N}$ is more dominant as compared to the fusion of fragment $^{11}\mathrm{B}$ with $^{154}\mathrm{Sm}$ target due to the smaller value of $\ensuremath{\alpha}$ breakup threshold energy $({E}_{\mathrm{B}.\mathrm{U}.}^{\ensuremath{\alpha}})$. The measured forward recoil range distributions of evaporation residues produced through $\ensuremath{\alpha}$ emitting channels provide experimental signature of strong clustering in $^{19}\mathrm{F}$ projectile as $\ensuremath{\alpha}$ and $^{15}\mathrm{N}$. The incomplete fusion strength function has also been deduced from the measured recoil range distributions and found to be compatible with those deduced from the measured excitation functions for the same system and beam energy.