Method of separable approximation for Skyrme force and effects of complex configurations in structure of exotic nuclei
News, 30 January 2023
A series of scientific papers “Method of separable approximation for Skyrme force and effects of complex configurations in the structure of exotic nuclei” received the JINR Encouraging Prize for 2021. The works of the series were written by an international group of scientists, including three authors from the nuclei structure sector of the Bogoliubov Laboratory of Theoretical Physics JINR Nikolay Arsenyev, Viktor Voronov, and Alexey Severyukhin.
The study of the properties of medium-heavy and heavy nuclei far from the stability line requires the development of new theoretical approaches. In the series of works, making use of the energy density functional authors suggest a new method allowing to the separable form of the Hamiltonian. The method enables one to perform the calculations in very large configurational spaces.
The generalised equations of the quasiparticle-phonon model have been applied to the study of low-energy spectra of neutron-rich nuclei, in particular, the mixed-symmetry states. The self-consistency condition in the particle-particle channel gave an opportunity to study the role of the surface interaction for the g-factor description in the case of the 2+ states. The influence of complex configurations on the characteristics of giant and pygmy resonances was investigated. Anharmonic effects weakly affect the width of the giant dipole resonance (GDR). This effect is crucial for describing the width in the case of the isoscalar giant monopole and quadrupole resonances.
The inclusion of two-phonon configurations gives a considerable contribution to low-energy E1 strength and an essential increasing of the pygmy dipole resonance width of neutron-rich nuclei. Authors have studied for the first time the properties of the double-γ decay of the lowest quadrupole state. It is shown that the γγ-decay width is sensitive to the mixing of the simple and complex configurations. The one-phonon GDR configuration and the two-phonon configuration [GDR ⊗ 21+] play a key role in the width calculation. The generalised electric dipole polarizability is discussed as a new observable.
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- Severyukhin A. P., Arsenyev N. N., Pietralla N., Werner V. Impact of variational space on M1 transitions between first and second quadrupole excitations in 132,134,136Te. // Phys. Rev. C. — 2014. — Vol. 90. — P. 011306(R)-1–5.
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- Severyukhin A. P., Arsenyev N. N., Pietralla N., Werner V. Proton-neutron structure of first and second quadrupole excitations of 90Sr. // Eur. Phys. J. A. — 2018. — Vol. 54. — P. 4-1–8.
- Arsenyev N. N., Severyukhin A. P., Voronov V. V., Van Giai Nguyen Low-energy E1 strength distributions of 68Ni.// Phys. Part. Nucl. — 2019. — Vol. 50. — № 5. — P. 528–531.
- Arsenyev N. N., Severyukhin A. P. Origin of low- and high-energy monopole collectivity in 132Sn. // Universe. — 2021. — Vol. 7. — № 5. — P. 145-1–13.
- Severyukhin A. P., Arsenyev N. N., Pietralla N. First calculation of the γγ-decay width of a nuclear 21+ state: the case of 48Ca. // Phys. Rev. C. — 2021. — Vol. 104. — P. 024310-1–6.