Impact of breakup like processes on Fusion and Elastic scattering of weakly bound projectiles from medium mass target

This talk was delivered by Mr Shaikh in defense of his Ph.D thesis work done under the supervision of Prof Subinit Roy. Abstract: The measurements of fusion and back angle quasi-elastic excitation functions have been performed for the weakly bound projectiles 6,7Li with 64Ni (Z=28, N=36) target. The primary motivations is to understand the effect of direct reaction channels, like transfer or breakup, on fusion and elastic scattering of these systems around the barrier. The coupling of the entrance channel with other direct reactions channels splits the nominal Coulomb barrier into multiple barriers. Hence, the important tool barrier distribution functions have also been extracted to probe the importance of these direct reaction channels. The total fusion (TF) and complete fusion (CF) excitation functions at energies around the Coulomb barrier have been measured by detecting the online characteristic γ-rays of the residues. The CF cross sections exhibit an average suppression of ~13% for more weakly bound projectile 6Li compared to 6.5% for 7Li at above barrier energies. Comparing the observations of fusion suppression of these two projectiles with different targets at above barrier energies, it can be concluded that the suppression, in general, decreases with the decrease of target-projectile charge product. But no suppression is observed for TF cross sections in this energy region for both the systems. At energies below the barrier, both the TF and the CF cross sections are enhanced for 6Li + 64Ni and 7Li + 64Ni. The barrier distributions have been extracted from fusion and quasi-elastic excitation functions for the both systems. The coupled channel calculations have been performed explain the experimental observations.