engleski

How does fusion hindrance show up in medium-light systems ? The case of 48Ca + 48Ca

The fusion excitation function of 48Ca+48Ca has been remeasured above and well below the Coulomb barrier, thereby largely extending the energy range of a previous experiment down to very low cross sections. This system has a negative Q-value for compound nucleus formation. The fusion cross section decreases steadily below the barrier with no conspicuous change of slope below ~300microbarn. Coupled-channels calculations using Woods-Saxon potential indicate that a large diffuseness parameter is needed to reproduce the sub-barrier cross sections. A close analogy with the case of 36S+48Ca with positive Q value is pointed out. The sign of the Q-value does not influence fusion cross sections down to the 300-600 nb level.

Heavy-ion fusion ; sub-barrier cross sections ; coupled-channels model

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