Coupled reaction channel analysis of one- and two-nucleon transfer in ^28 Si+ ^90,94 Zr

Coupled reaction channel approach has been quite successful in describing the mechanism of multi-nucleon transfer in heavy ion-induced reactions. However, considerable ambiguities exist in the choice of potential parameters and the states of participating nuclides that should be coupled for a given reaction channel. Here we report simultaneous analysis of both angular distributions and excitation functions for one- and two-nucleon transfer in the systems ^28 Si+ ^90,94 Zr within the coupled reaction channel formalism. Spectroscopic amplitudes are obtained from the literature and large-scale shell model calculations. The uncertainties in the cross sections, introduced by the choice of effective interactions in shell model, are also investigated. While one-nucleon transfer in the system ^28 Si+ ^94 Zr have been well reproduced by inclusion of the ground and the first excited states of projectile-likes in the exit channel, more states of the same are to be coupled for the system ^28 Si+ ^90 Zr. Observed bell-shaped angular distribution of one-proton stripping channel in ^28 Si+ ^94 Zr is found to be caused by a large contribution of direct transfer from the ground and the first excited states of projectile-likes. In contrast, a flat angular distribution of one-proton stripping channel in ^28 Si+ ^90 Zr appears to have been caused by a large number of indirect transitions. For two-nucleon transfer, both one-step and two-step processes have been considered. Reasonable reproduction of measured cross sections has been achieved by application of the extreme cluster model for the transfer of a pair of nucleons. No arbitrary scaling of the theoretical results has been necessary and only a minor variation of the binding radius has been allowed in our calculations. More such studies are warranted for mitigating the ambiguities in coupled reaction channel description of multi-nucleon transfer.