Fusion hindrance for Al27+Sc45 and other systems with a positive Q value

Abstract

Fusion evaporation cross sections for the Al27+Sc45 (Q=9.63 MeV) system are measured down to about 300 nb. Deviations from standard coupled-channels calculations were observed in this system at the lowest energies. The steep fall-off of the fusion cross sections can be reproduced by calculations using a shallow potential model, which was originally developed to explain the hindrance behavior of heavy-ion fusion in medium-mass systems with negative Q values. Comparisons of the hindrance behavior between the present experiment and other systems, for example, Si28+Si30 (Q=14.3 MeV) and S36+Ca48 (Q=7.55 MeV) are presented. © 2010 The American Physical Society.