Evidence of proton-proton correlations in the 116Sn+60Ni transfer reactions

One and two proton transfer channels have been measured in 116 Sn+ 60 Ni with the magnetic spectrometer PRISMA by making an excitation function at several bombarding energies, from above to well below the Coulomb barrier. The total kinetic energy loss distributions show the predominance of quasi-elastic processes in the sub-barrier regime. The data have been compared with calculations performed with the GRAZING program, based on semiclassical formalism, and in the Distorted Wave Born Approximation (DWBA), which provided a good theoretical description of the extracted transfer probabilities for the one proton transfers. The much larger values of the experimental two proton transfers compared with those evaluated within an independent particle transfer mechanism, indicate the presence of strong proton- proton correlations. The results complement the ones of the previously analyzed one- and two-neutron transfers, providing significant new information on the subject compared to past works.