Dynamics of two-neutron transfer reactions with the Borromean nucleus ${}^6\mathrm{He}$

Low-energy two-neutron transfer reactions with Borromean nuclei (like ${}^6\mathrm{He})$ are shown to be an effective instrument for studying both the structure of such nuclei and the dynamics of nuclear reactions with their participation. A four-body model is developed to describe such two-nucleon transfer processes within the distorted-wave Born approximation. A realistic three-body bound-state wave function of ${}^6\mathrm{He}$ is used in the calculations and the role of its spatial localization is thoroughly studied. In particular, it is found that the “dineutron” configuration of the ${}^6\mathrm{He}$ nucleus gives the dominant contribution to the two-neutron transfer cross sections. Detailed analysis of the dynamics of these reactions is carried out and the possibilities of using multineutron transfer reactions for studying the structure of other exotic nuclei, in particular ${}^8\mathrm{He},$ are discussed.