Collectivity in neutron rich nuclei above ¹³²Sn core

Full text of publication follows. New era for theoretical and experimental nuclear structure is dawning due on the one side to the number of successful approaches ranging from empirical fits of the interactions, to deriving them microscopically from the bare NN potential, and on the other side to the experiments progress by the availability of radioactive ion beams, which may provide a stringent test for the validation of various theoretical models. Within the shell model, special attention has been focused to the neutron rich nuclei beyond ¹³²Sn, where many studies have been achieved by the calculations of the low-lying state energies and isomeric transitions of tin isotopes ^{134,136,138,140}Sn. In the same context, making use of a realistic interaction derived from N3LO and including the model space above the closed core ¹³²Sn, the energy levels and the electromagnetic transition rates of chain of even-even nuclei with 52 ≤ Z ≤ 60 will be presented and compared to the experimental data. I will mainly focus to the appearance of a deformation and the evolution of the collectivity in the chain of isotones N=86, where several signatures support the presence of triaxial γ-band in this mass region. These applications constitute a stringent test of our effective interaction, and our predictions can be provided as benchmark for future experimental measurements. (authors)