Four-nucleon and α-particle transfer between heavy nuclei

Using a magnetic spectrometer, data on transfer reactions are obtained in the 208Pb + 144Sm system at energies below the Coulomb barrier. They are analysed with respect to the properties of the transfer of two protons and two neutrons. These reactions correspond to α-particle removal or addition as well as to two different double-charge exchange reactions. Using the semiclassically defined probabilities for the transfer of two protons and two neutrons, as obtained from the measured data, the four-nucleon transfer can be quantitatively described in three cases by the sequential independent transfer of protons and neutrons in the same or different directions. (Author)