Novel insights into transfer processes in the reaction 16O+208Pb at   sub-barrier energies
  The collision of the doubly-magic nuclei $^{16}$O+$^{208}$Pb is a benchmark in nuclear reaction studies. Our new measurements of back-scattered projectile-like fragments at sub-barrier energies show show that transfer of 2 protons ($2p$) is much more probable than $\alpha$-particle transfer. $2p$ transfer probabilities are strongly enhanced compared to expectations for the sequential transfer of two uncorrelated protons; at energies around the fusion barrier absolute probabilities for two proton transfer are similar to those for one proton transfer. This strong enhancement indicates strong $2p$ pairing correlations in $^{16}$O, and suggests evidence for the occurrence of a nuclear supercurrent of two-proton Cooper pairs in this reaction, already at energies well below the fusion barrier. 
M. Evers and C. Simenel and M. Dasgupta and D. J. Hinde and D. H.   Luong and R. Rafiei and R. du Rietz
nucl-ex