Unexpected results in neutron-rich radioactive beams induced fusion...

The fission-fragment beams at HRIBF provide a unique opportunity for studying
the mechanisms of fusion involving nuclei with large neutron excess. To
explore the role of transfer couplings, fusion excitation functions have been
measured using neutron-rich radioactive $^{132}$Sn beams incident on $^{40}$Ca
and $^{58}$Ni targets. The sub-barrier fusion enhancement for
$^{132}$Sn+$^{40}$Ca is larger than that for $^{132}$Sn+$^{58}$Ni although the
neutron transfer Q-values are similar for the two reactions. The fusion
excitation function for $^{46}$Ti+$^{124}$Sn has been measured in an attempt
to resolve the differences observed in $^{132}$Sn+$^{40}$Ca and
$^{132}$Sn+$^{58}$Ni.