Role of neutron transfer on fusion barrier distributions of the 28,30Si+124Sn systems

The fusion barrier distributions for Si-28,Si-30+Sn-124 systems were extracted from quasielastic excitation function measurements at backward angles. The experimental barrier distributions were then compared with coupled-channel (CC) calculations. The fusion barrier distribution for the Si-30+Sn-124 reaction was well reproduced by the CC calculations with the inclusion of projectile and target inelastic couplings and only one possible positive Q-value 2n-transfer channel coupling using the CCFULL code. However, CC calculations with similar coupling schemes for inelastic excitation of target and projectile with the 4n-transfer channel corresponding to the highest positive Q value failed to reproduce the barrier distribution for the Si-28+Sn-124 reaction, because it has many positive Q-value multi-neutron transfer channels. A better agreement between the experimental fusion barrier distribution for the Si-28+Sn-124 system and the prediction of semiempirical CC calculations based on the Zagrebaev framework [V. I. Zagrebaev, Phys. Rev. C 67, 061601(R) (2003)] was obtained only after considering positive Q-value multi-neutron transfer couplings. The sensitivity of the fusion barrier distribution to the hexadecapole deformation parameter beta(4) of the projectile was also discussed.