Fusion hindrance for a positive Q-value system

An excitation function for the fusion reaction Si-28 + Si-30 (Q=14.3MeV) has been measured down to 40 mu b. Deviations from the behavior predicted by the optical model and standard coupled-channels calculations have been observed in this system. The fusion cross sections can be reproduced by a shallow potential model well, which was originally developed to explain the hindrance of heavy-ion fusion for systems with negative Q-values.