Optical model analysis of elastic scattering and fusion in reactions with weakly bound projectiles around the Coulomb barrier

摘要

A simultaneous Distorted Wave Born Approximation calculation of elastic scattering, fusion and breakup cross sections for energies around the Coulomb barrier is presented for reactions involving weakly bound projectiles on a medium size target. A Woods-Saxon optical potential is used, for which the imaginary part is split into a volume part W-F which is responsible for fusion reactions and a surface part W-DR which accounts for direct reactions. Energy dependent forms for W-F and W-DR are then extracted from recent data. By the use of the dispersion relation, the corresponding real polarization potentials V-F(E) and V-DR(E) are also determined. As a result, a new type of anomaly is present, the so called Breaukup Threshold Anomaly.