A coupled-channel analysis of scattering, two-neutron transfer and fusion in medium heavy-ion collisions

Scattering, two-neutron transfer and fusion processes are analyzed in the s cope of a coupled-channel formalism using collective excitations in the rea l and a gauge space, A small set of collective states simplifies the calcul ation of form factors allowing an easy evaluation of interesting physical q uantities such as cross sections, probability densities, currents, fusion r ates, spin distributions and probability sources and sinks in the different channels. The availability of these quantities makes possible an insight t hat clarifies the underlying reaction mechanisms. In particular, a barrier, modified by the coupling between channels, is introduced, permitting an in terpretation of relevant characteristics of the interaction processes, The system O-18 + Ni-60 is specifically studied at energies of E-lab = 63 and 6 5 MeV for the scattering and two-neutron transfer, respectively, and at ene rgies around the Coulomb barrier for fusion. In this case, it can be observ ed that the presence of the transfer channel plays a catalytic role in the enhancement of the fusion cross section by incrementing the contribution of the dispersion channels. (C) 2000 Elsevier Science B.V. All rights reserve d.