Simultaneous optical model analysis of elastic scattering, fusion, and breakup for the 9Be+144Sm system at near-barrier energies

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 Be-9 on the medium size target Sm-144. 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-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-DR and W-DR Of U-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 Be-9 + Sm-144. Within this formalism, the effect of breakup reactions on complete fusion is studied by turning on and off the potentials responsible for breakup reactions.