Threshold anomaly in the 6,7Li + 232Th reactions

The measurements of the elastic scattering angular distributions determine parameters of the real and imaginary parts of the optical model potential parameters. From systematic analysis of elastic scattering measurements involving tightly bound nuclei, the so called 'threshold anomaly' (TA) has been observed in a number of systems. This has been understood in terms of couplings of elastic channel to the direct reaction channels that generate an additional attractive real dynamic polarization potential. In the present work, the elastic scattering for 6,7Li + 232Th systems has been investigated through very precise and complete angular distribution measurements at energies around the Coulomb barrier. The main objective was to observe the TA/BTA in those weakly bound projectiles in terms of dispersion relation