Gamow-Teller transitions and a separable approximation for Skyrme interactions

Thursday 5 Sept 2013, 13:30 → 15:00 Asia/Tokyo

Nishina Hall (RIKEN Wako)

Date : September 5th, 2013 (Thursday) Time : 13:30 -- 15:00 Place : Nishina hall Title : Gamow-Teller transitions and a separable approximation for Skyrme interactions Speaker : Alexey P. Severyukhin Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna, Russia Abstract: One of the successful tools for nuclear structure studies is the quasiparticle random phase approximation (QRPA) with the self-consistent mean-field derived by making use of the Skyrme interaction. Many charge-exchange versions of it were developed during the last decade. Their common feature is that they allow to relate the properties of the ground states and excited states through the same energy density functional. On the other hand, it would be desirable to extend the description beyond the QRPA scheme in order to include damping effects observed experimentally. Making use of separable residual interaction one can perform the spin-isospin excitation calculations in large configuration spaces since there is an opportunity to avoid matrices whose dimensions grow with the size of configuration space. For the same reasons, we develop the finite rank separable approximation for the Skyrme interactions [1,2] that enables one to perform the charge-exchange calculations in the large configuration space [3,4]. In this talk we briefly describe our method for the charge-exchange excitations and present our studies of properties of the Gamow-Teller states in wide excitation energy regions. In particular, the effects of the tensor correlations and 2p-2h fragmentation on the strength distributions will be discussed. [1] Nguyen Van Giai, Ch. Stoyanov and V.V. Voronov, Phys. Rev. C57, 1204 (1998). [2] A. P. Severyukhin, V. V. Voronov and Nguyen Van Giai, Eur. Phys. J. A22, 397 (2004). [3] A. P. Severyukhin, V. V. Voronov and Nguyen Van Giai, Prog. Theor. Phys. 128, 489 (2012). [4] A. P. Severyukhin and H. Sagawa, EPJ Web of Conferences 38, 06001 (2012).