Correlated EoM and Distributions for A = 6 Nuclei

Energy spectra and electromagnetic transitions of nuclei are stronglydepending from the correlations of the bound nucleons. Two particlecorrelations are responsible for the scattering of model particles either tolow momentum- or to high momentum-states. The low momentum states form themodel space while the high momentum states are used to calculate the G-matrix.The three and higher order particle correlations do not play a role in thelatter calculation especially if the correlations induced by the scatteringoperator are of sufficient short range. They modify however, via the long tailof the nuclear potential, the Slater determinant of the A particles bygenerating excited Slater's determinants. In this work the influence of thecorrelations on the level structure and ground state distributions of even openshell nuclei is analyzed via the boson dynamic correlation model BDCM. Themodel is based on the unitary operator $e^S$ ({\it S} is the correlationoperator) formalism which in this paper is presented within a non perturbativeapproximation. The low lying spectrum calculated for $^6$Li reproduce very wellthe experimental spectrum while for $^6$He a charge radius slightly larger thanthat obtained within the isotopic-shift (IS) theory has been calculated. Goodagreement between theoretical and experimental results has been obtainedwithout the introduction of a genuine three body force.Comment: 25 pages 4 figures. To be published in the Progress Theoretical Physic