Scaling limit analysis of Borromean halos

Abstract

The analysis of the core recoil momentum distribution of neutron-rich isotopes of light exotic nuclei is performed within a model of halo nuclei described by a core and two neutrons dominated by the s-wave channel. We adopt the renormalized three-body model with a zero-range force, which accounts for the Efimov physics. This model is applicable to nuclei with large two-neutron halos compared to the core size, and a neutron–core scattering length larger than the interaction range. The halo wave function in momentum space is obtained by using as inputs the two-neutron separation energy and the energies of the singlet neutron–neutron and neutron–core virtual states. Within our model, we obtain the momentum probability densities for the Borromean exotic nuclei Lithium-11 ( 11 Li), Berylium-14 ( 14 Be) and Carbon-22 ( 22 C). A fair reproduction of the experimental data was obtained in the case of the core recoil momentum distribution of 11 Li and 14 Be, without free parameters. By extending the model to 22 C, the combined analysis of the core momentum distribution and matter radius suggest (i) a 21 C virtual state well below 1 MeV; (ii) an overestimation of the extracted matter 22 C radius; and (iii) a two-neutron separation energy between 100 and 400 keV.