Optical model parallel description of elastic, fusion and breakup cross sections for systems with weakly bound projectiles

摘要

A brief description is presented of the results obtained in recent years for the simultaneous analysis of elastic and fusion cross section data of nuclear reactions for several nuclear systems with weakly bound and halo projectiles. The method used in this description, consists of simultaneously determine the parameters of fusion U_F and direct reaction U_(DR) polarization potentials of Woods-Saxon geometric shapes, that fit the elastic and fusion data. As a matter of fact, U_F is an energy dependent potential, with real V_F and imaginary W_F components, that is responsible for fusion reactions. Similarly, U_(DR) is also energy dependent with real V_(DR) and imaginary W_(DR) parts, that accounts for direct reactions. A general finding for all the systems presented is that, the real and imaginary parts of the fusion potential and direct reaction potentials, are related by a dispersion relation and their energy dependence around and below the Coulomb barrier, show the so-called Breakup Threshold Anomaly. The effect of breakup reactions on fusion cross sections is studied by analyzing the separate effect of the absorption potential W_(DR) and the fusion barrier rising produced by V_(DR).