Two-neutron exchange observed in the 6He+4He reaction. Search for the "di-neutron" configuration of 6He

Elastic scattering and reactions of light exotic beams

“…All three data sets show the backward angle rise in cross section usually considered characteristic of elastic transfer. The DWBA analysis of Ter-Akopian et al [55], using a 6 He wave function derived from that given by the solution of the exact three-body problem of Zhukov et al [58], obtained good agreement with the backward angle data under this assumption, and further concluded that the di-neutron configuration dominates the 6 He ground state wave function. Raabe et al [56] came to a similar conclusion regarding the importance of two-neutron transfer in their data, an optical model analysis based on a double-folding plus parity-dependent potential, the latter simulating 2n transfer, providing a good description of the data.…”

“…Elastic scattering data are available at centre of mass energies of 60.3 [55], 11.6 [56,57] and 15.9 MeV [56]. These data are candidates for showing the elastic transfer phenomenon through two-neutron transfer between the two 4 He cores, and the main motivation of these studies was to probe the relative importance of the ''di-neutron'' and ''cigar'' configurations of the valence neutrons in the 6 He ground state.…”

Radioactive ion beam physics at the cyclotron research centre Louvain-la-Neuve

“…Later works used these data and those obtained at a higher energy at the Flerov Institute in Dubna [55], to investigate in more detail the possible sequential transfer of the two neutrons, which could have originated from a cigar configuration of the halo neutrons. In both Refs.…”

Calculations of 6He + p elastic-scattering cross-sections using folding approach and high-energy approximation for the optical potential

“…Nowadays, a substantial amount of experimental data exists for the cross sections of 6 He+p elastic scattering at different energies. For example, proton elastic scattering angular distributions were measured at incident energies less than 100 MeV/N for 6 He, namely 25.2 [1,2,3,4], 38.3 [5], 41.6 [6,7,8], and 71 MeV/N [9,10] and at energy of 700 MeV/N for He and Li isotopes (e.g. refs.…”