Influence of projectile α-breakup threshold on complete fusion

Complete fusion excitation functions for B11,10+Tb159 have been measured at energies around the respective Coulomb barriers, and the existing complete fusion measurements for Li7+Tb159 have been extended to higher energies. The measurements show significant reduction of complete fusion cross sections at above-barrier energies for both the reactions, B10+Tb159 and Li7+Tb159, when compared to those for B11+Tb159. The comparison shows that the extent of suppression of complete fusion cross sections is correlated with the α-separation energies of the projectiles. Also, the two reactions, B10+Tb159 and Li7+Tb159 were found to produce incomplete fusion products at energies near the respective Coulomb barriers, with the α-particle emitting channel being the favoured incomplete fusion process in both the cases.