Single and pair neutron transfers at sub-barrier energies

摘要

Multinucleon transfer cross sections in the 96Zr+40Ca system have been measured, in inverse kinematics, atnbombarding energies ranging from the Coulomb barrier to ∼25% below. Targetlike recoils have been identifiednin A, Z and velocity with the large solid angle magnetic spectrometer PRISMA. The experimental data for oneandntwo-neutron transfer channels have been compared with semiclassical microscopic calculations. For thentwo-neutron transfer channels the relevance of the transitions to the ground state and to the 0+ excited statesnof 42Ca are discussed by employing, for the reaction mechanism, the successive approximation. It is found thatnthe transition to the 0+ state at ∼6 MeV, whose wave function is dominated by the two neutrons in the 2p3/2nshell, is much larger than the ground state one. The comparison with the inclusive data reveals that transitions tonstates with high multipolarity and non-natural parity are important. This suggests that more complex two-particlencorrelations have to be incorporated in the treatment of the transfer process.