New analysis method of the halo phenomenon in finite many-fermion systems. First applications to medium-mass atomic nuclei

摘要

A new analysis method to investigate halos in finite many-fermion systems isdesigned, as existing characterization methods are proven to beincomplete/inaccurate. A decomposition of the internal wave-function of the{$N$-body} system in terms of overlap functions allows a model-independentanalysis of medium-range and asymptotic properties of the internal one-bodydensity. The existence of a spatially decorrelated region in the densityprofile is related to the existence of three typical energy scales in theexcitation spectrum of the {$(N-1)$-body} system. A series of model-independentmeasures, taking the internal density as the only input, are introduced. Thenew measures allow a quantification of the potential halo in terms of theaverage number of fermions participating to it and of its impact on the systemextension. Those new "halo factors" are validated through simulations andapplied to results obtained through energy density functional calculations ofmedium-mass nuclei. Performing spherical Hartree-Fock-Bogoliubov calculationswith state-of-the-art Skyrme plus pairing functionals, a collective halo ispredicted in drip-line Cr isotopes, whereas no such effect is seen in Snisotopes.