Hindrance of complete fusion in the Li-8+Pb-208 system at above-barrier energies

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Article Number: 044605


The At-211,At-212 yields resulting from the interaction of the radioactive projectile Li-8 with a Pb-208 target have been measured at energies between 3 and 8.5 MeV above the Coulomb barrier. They are signatures for fusion of the whole charge but not necessarily the whole mass of the projectile, so they are included in a corresponding operational definition of complete fusion. Within this definition, a fusion suppression factor of 0.70 +/- 0.02 (stat.) +/- 0.04 (syst.) is deduced from a comparison to a one-dimensional barrier-penetration-model calculation using parameters extrapolated from values for Li-6,Li-7 + Bi-209 and Be-9 + Pb-208 taken from the literature. Possible incomplete fusion processes are discussed and the results are fitted with a phenomenological model assuming breakup prior to fusion followed by capture of a Li-7 fragment.