Characterization of vorticity in pygmy resonances and soft-dipole modes with two-nucleon transfer reactions

. The properties of the two-quasiparticle-like soft E 1-modes and Pygmy Dipole Resonances (PDR) have been and are systematically studied with the help of inelastic and electromagnetic experiments which essentially probe the particle-hole components of these vibrations. It is shown that further insight in their characterisation can be achieved with the help of two-nucleon transfer reactions, in particular concerning the particle-particle components of the modes, in terms of absolute differential cross sections which take properly into account successive and simultaneous transfer mechanisms corrected for non-orthogonality, able to reproduce the experimental findings at the 10% level. The process 9 Li( t , p ) 11 Li(1 - ) is discussed, and absolute cross sections predicted.