The role of transfer couplings in the fusion of Sn+Ni and Te+Ni systems

Evaporation residue and fission cross sections have been measured for the radioactive $^{132}$Sn+$^{58}$Ni and stable $^{130}$Te+$^{58,64}$Ni systems at energies near the Coulomb barrier. Through a comparison with previous Sn+Ni measurements, the role of transfer couplings on the heavy-ion fusion has been examined. While the number of positive Q-value neutron transfer channels varied widely between the different Sn+Ni and Te+Ni systems, the reduced excitation functions were equivalent. This is in contrast to a number of previous studies where large enhancements in the sub-barrier fusion cross sections were observed in systems with positive Q-value neutron transfer channels. The present results suggest a significant change in the influence of transfer couplings on the fusion process for the Sn+Ni and Te+Ni systems. This work was supported by DOE Office of Nuclear Physics