The effect of weak binding of ${}^9\mathrm{Be}$ on complete fusion has been explored through the study of complex fragment emission in ${}^{20}\mathrm{Ne}+{}^9\mathrm{Be}$ reaction. The yields of the fragments ${}^{6,7}\mathrm{Li}$ and ${}^{7,9}\mathrm{Be}$ emitted from the excited compound nucleus ${}^{29}\mathrm{Si}^{*}$ have been compared with the respective statistical model predictions. Emission of same fragments from another close-by compound nucleus ${}^{28}\mathrm{Si}^{*}$ at similar excitation energy, formed by the fusion of two strongly bound nuclei, ${}^{16}\mathrm{O}+{}^{12}\mathrm{C}$, has been studied for comparison. It has been observed that for the system ${}^{16}\mathrm{O}+{}^{12}\mathrm{C}$, the yields of ${}^{6,7}\mathrm{Li}$ and ${}^{7,9}\mathrm{Be}$ fragments are close to the predictions of the statistical model. However, for the ${}^{20}\mathrm{Ne}+{}^9\mathrm{Be}$ system, although the experimental yield pattern follows the statistical model prediction, there is substantial reduction in yield for all detected fragments. These observations have been attributed to the suppression of complete fusion in ${}^{20}\mathrm{Ne}+{}^9\mathrm{Be}$ system due to the weak binding of ${}^9\mathrm{Be}$, a dynamical effect which is not incorporated in the conventional statistical models. It is the first time that a clear signature of the suppression of complete fusion in light systems involving weakly bound nucleus has been observed in complex fragment emission from fully equilibrated composite produced in fusion well above the barrier.

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• Breakup reactions
• Low & intermediate energy heavy-ion reactions
• Nuclear fragmentation
• Nuclear fusion