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Statut Confirmé
Série IPN-THEO
Domaines nucl-th
Date Mercredi 6 Décembre 2017
Heure 11:30
Institut IPN
Salle Bâtiment 100, Salle A015
Nom de l'orateur Arsenyev
Prenom de l'orateur N. N.
Addresse email de l'orateur
Institution de l'orateur Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna, Russia
Titre Microscopic Description of Pygmy Dipole Resonances in Neutron-rich Ca Isotopes
Résumé The structure of exotic neutron-rich nuclei is one of the main fields of interest in contemporary nuclear physics research. Much attention has been devoted to the ef- fects of varying the ratio between the proton Z and neutron N numbers on different nuclear structure characteristics of nuclei away from their valley of β-stability. One of the phenomena associated with the change in N/Z ratios is the pygmy dipole res- onance (PDR). One of the successful tools for describing the PDR is the quasiparticle random phase approximation (QRPA) with the self-consistent mean-field derived from Skyrme energy density functionals (EDF). Such an approach can describe the properties of the low-lying states reasonably well by using existing Skyrme inter- actions. Due to the anharmonicity of the vibrations there is a coupling between one-phonon state and more complex configurations. The main difficulty is that the complexity of calculations beyond standard QRPA increases rapidly with the size of the configuration space, and one has to work within limited spaces. Using a finite rank separable approximation for the residual particle-hole interaction derived from the Skyrme forces one can overcome this numerical problem. As an illustration, we study the properties of the low-lying dipole states in the even- even nuclei 40 − 58 Ca. Using the same set of the EDF parameters we describe available experimental data for 40,44,48 Ca and give predictions for 50 − 58 Ca. In particular, we examine the impact of the coupling between one- and two-phonon states on the low- energy E1 strength of 40,44,48 Ca. We predict a strong increase of the summed E1 strength below 10 MeV with increasing neutron number from 48 Ca.
Numéro de preprint arXiv
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  • 2017_12_06_N_Arsenyev.pdf (221019 bytes) OPEN

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