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-HartreeFock approach at zero temperature. We consider the Argonne nu(18) 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 1 fm(-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 similar to 110 fm. Implications of these findings are presented and discussed.