NEAR-BARRIER HEAVY-ION FUSION (PANEL DISCUSSION)

We are approaching a semi-quantitative understanding of the role of the coupling of shape and transfer degrees of freedom in the enhancement of near and sub-barrier fusion cross section, although there remains some debate about the relative importance of the different degrees of freedom. The information content in fusion excitation functions is limited and it is therefore important to obtain additional information such as higher moments of the partial wave distribution. The present status of information obtained with different probes will be critically discussed. Among the open problems in sub-barrier fusion is the importance of a neck degree of freedom and a concomitant departure of the inertial mass from the reduced mass. A coupled channels description in terms of the asymptotic exit channels may only converge slowly.