Core momentum distribution in two-neutron halo nuclei

Abstract The core momentum distribution of a weakly-bound neutron–neutron–core exotic nucleus is computed within a renormalized zero-range three-body model, with interactions in the s-wave channel. The halo wave-function in momentum space is obtained by using as inputs the two-body scattering lengths and the two-neutron separation energy. The core momentum densities are computed for 11 Li, 14 Be 20 C and 22 C. The model describes the experimental data for 11 Li, 14 Be and to some extent 20 C. The recoil momentum distribution of the 20 C from the breakup of 22 C nucleus is computed for different two-neutron separation energies, and from the comparison with recent experimental data the two-neutron separation energy is estimated in the range 100 ≲ S 2 n ≲ 400 keV . The recoil momentum distribution depends weakly on the neutron- 20 C scattering length, while the matter radius is strongly sensitive to it. The expected universality of the momentum distribution width is verified by also considering excited states for the system.