Probing of incomplete fusion dynamics by spin-distribution measurement

Aiming to probe incomplete fusion dynamics in 16O + 169Tm system, spin-distributions of various reaction products populated via xn-, α/2αxn-channels have been measured at E≈5.6MeV/nucleon. Prompt γ-rays in coincidence with fast charged particles (Z=1,2) have been recorded to achieve the information about involved reaction processes on the basis of their experimentally observed spin-populations during de-excitation. The experimentally observed spin-distributions for direct-α-emitting channels (associated with incomplete fusion) have been found to be distinctly different than that observed for fusion-evaporation (complete fusion) channels. The mean value of driving input angular momenta associated with various direct-α/2αxn-channels have been found to be higher than that observed for fusion-evaporation xn/αxn-channels, and increases with direct-α-multiplicity in forward cone. Experimentally measured, normalized production yields of fusion-evaporation xn/αxn-channels have been found to be in good agreement with the predictions of theoretical model code PACE4. Further, in order to understand the feeding probability in both complete and incomplete fusion reaction products, an attempt has been made to generate feeding intensity profiles from spin-distribution data. It has been observed that the complete fusion products are strongly fed over a broad spin range, while incomplete fusion products are found to be less fed and/or the population of lower spin states are strongly hindered.