A simultaneous optical model calculation of elastic scattering, complete fusion, and breakup cross sections for energies around the Coulomb barrier is presented for reactions involving the weakly bound projectile ${}^9\mathrm{Be}$ on the medium size target ${}^{144}\mathrm{Sm}$. In the calculations, the nuclear polarization potential $U$ is split into a volume part $U_F$, which is responsible for fusion reactions, and a surface part $U_{\mathrm{DR}}$, which accounts for direct reactions. A simultaneous ${\chi }^2$ analysis of elastic and complete fusion data shows that the extracted optical potential parameters of the real $V_F$ and imaginary $W_F$ parts of $U_F$ and the corresponding parts $V_{\mathrm{DR}}$ and $W_{\mathrm{DR}}$ of $U_{\mathrm{DR}}$ satisfy separately the dispersion relation. Energy-dependent forms for the fusion and direct reaction potentials indicate that, at the strong absorption radius, the direct reaction potentials dominate over the fusion potentials$.$ Moreover, the imaginary direct reaction potential results in a rather smooth function of $E$ around the barrier energy. These findings show that the threshold anomaly, usually present in reactions with tightly bound projectiles, is not exhibited for the system ${}^9\mathrm{Be}+{}^{144}\mathrm{Sm}$. Within this formalism, the effect of breakup reactions on complete fusion is studied by turning on and off the potentials responsible for breakup reactions.

• Received 8 February 2008

DOI:https://doi.org/10.1103/PhysRevC.77.054606