[Triumf-seminars] TRIUMF Seminar today at 14:00

[postmaster at admin.triumf.ca]

Date/Time: Thu 2007-10-04 at 14:00

Location:  MOB Conference Room 

Speaker:   Vincent Rotival (MSU/NSCL and Bruyeres-Le-Chatel)

Title:     Halo Phenomenon in Medium-Mass Nuclei: New Analysis Method and Applications

Abstract: Halos in few- or many-body quantum systems is still the focus of many theoretical and experimental studies. Their very existence in medium-mass nuclei is an open question, whereas the characterization methods used to answer that question are incomplete and/or inaccurate. A new analysis method, based on a decomposition of the intrinsic wave function of the N-body system in terms of overlap functions, has been devised and allows a model-independent analysis of the asymptotic properties of the intrinsic one-body density. The existence of a spatially decorrelated region in the nuclear density profile is related to the existence of typical energy scales in the excitation spectrum of the (N-1)-body system. Several model-independent criteria, taking the density as the only input, are introduced. The latter criteria allow a precise quantification of halo systems in terms of the average number of participating nucleons and of their impact on the nuclear extension.

I will briefly present the key theoretical ingredients to the analysis method, and focus on its application to the results obtained through Energy Density Functional calculations of even-even spherical nuclei. In particular, I will show that a collective halo is predicted in a very few neutron-rich isotopes. The role of the pairing antihalo effect will also be investigated, as well as the influence of the parametrization of the Energy Density Functional. I will conclude by applying the analysis method to other mesoscopic quantum systems; e.g. to calculations of atom-positron and atom-positronium complexes as well as light nuclei.

Stimulants available 15 minutes before the talk.

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