Di-neutrons in neutron matter within a Brueckner-Hartree-Fock approach

Abstract

We investigate the appearance of di-neutron bound states in pure neutron matter within the Brueckner-Hartree-Fock approach at zero temperature. We consider the Argonne v18 and Paris bare interactions as well as chiral two- and three-nucleon forces. Self-consistent single-particle potentials are calculated by controlling explicitly singularities in the g matrix associated with bound states. Di-neutrons are loosely bound, with binding energies below 1 MeV, but are unambiguously present for Fermi momenta below 1fm-1 for all interactions. Within the same framework we are able to calculate and characterize di-neutron bound states, obtaining mean radii as high as ∼110 fm. Implications of these findings are presented and discussed.