A new analysis method to investigate halos in finite many-fermion systems is designed, as existing characterization methods are proven to be incomplete/inaccurate. A decomposition of the internal wave-function of the N -body system in terms of overlap functions allows a model-independent analysis of medium-range and asymptotic properties of the internal one-body density. The existence of a spatially decorrelated region in the density profile is related to the existence of three typical energy scales in the excitation spectrum of the (N −1)-body system. A series of model-independent measures, taking the internal density as the only input, are introduced. The new measures allow a quantification of the potential halo in terms of the average number of fermions participating to it and of its impact on the system extension. Those new "halo factors" are validated through simulations and applied to results obtained through energy density functional calculations of medium-mass nuclei. Performing spherical Hartree-Fock-Bogoliubov calculations with state-of-the-art Skyrme plus pairing functionals, a collective halo is predicted in drip-line Cr isotopes, whereas no such effect is seen in Sn isotopes.
32 Pages, 42 Figures. To be submitted to Phys. Rev. C back-to back with first part (nucl-th/0702050)The analysis method proposed in [V. Rotival and T. Duguet, nucl-th/0702050] is applied to characterize halo properties in finite quantum systems. First, the model independence of the method is highlighted by applying it to the results of many-body calculations of light and medium-mass nuclei as well as of atom-positron complexes. Second, the dependence of halo properties on the characteristics of the nuclear energy density functional used is studied through self-consistent Hartree-Fock-Bogoliubov calculations. It is found that (a) the low-density behavior of the pairing functional and the regularization/renormalization scheme must be chosen coherently to be physically sound (b) the overall impact of pairing correlations on halo properties is very significant and is the result of two competing effects (c) however, the detailed characteristics of the pairing functional has only little importance (d) halos properties depend significantly on the ingredients of the energy density functional that influence the location of single-particle levels; i.e. effective mass, tensor terms, saturation energy. Last but not least, large scale predictions of halos among all spherical even-even nuclei are performed using specific sets of particle-hole and particle-particle energy functionals. It is shown that halos in the ground state of medium-mass nuclei might only be found at the very limit of neutron stability for a limited number of elements
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