Europhys. Lett, 45 (3), pp. 296-300 (1999)
The role of virtual states in the appearance
of two-neutron halo
R. A. Ionescu and C. Hategan
Institute of Atomic Physics - P.O. Box MG-6, Bucharest, Romania
(received 2 April 1998; accepted in final form 23 November 1998)
PACS. 21.10Gv - Mass and neutron distributions.
PACS. 21.60 - Nuclear-structure models and methods.
PACS. 03.65Ge - Solutions of wave equations: bound states.
The existence of loosely bound, spatially extended states in a two-particle plus core system is studied. The description is given in the Schrödinger picture by treating the interactions in the scattering length approximation. The treatment supports the statement that the most favourable case for the appearance of the two-neutron halo is the existence of large negative neutron-core scattering length (a virtual state) besides the n-n virtual state.