LXXII International conference "Nucleus-2022: Fundamental problems and applications"

Microscopic description of isoscalar giant monopole resonance: the case of 48Ca

14 Jul 2022, 15:20

20m

Физический ф-т, 5-19

Oral talk (15 min + 5 min questions) Nuclear structure: theory and experiment

Speaker

Dr Nikolay Arsenyev (Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research)

Description

A comprehensive analysis of the isoscalar giant monopole resonance (ISGMR) has long been a subject of extensive theoretical and experimental research [1,2]. The ISGMR properties are presently an important problem not only from the nuclear structure point of view [2,3] but also because of the special role they play in many astrophysical processes such as prompt supernova explosions [4] and the interiors of neutron stars [5].
One of the successful tools for describing the ISGMR is the quasiparticle random phase approximation (QRPA) with the self-consistent mean-field derived from Skyrme energy density functionals (EDF) [2,3]. The study of the monopole strength distribution in the region of giant resonance involves taking into account a coupling between the simple particle-hole excitations and more complicated (two- and three-phonons) configurations [3,6]. 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 EDF one can overcome this numerical problem [7,8].
In the present report, we study the effects of the coupling between one-, two- and three-phonon terms in the wave functions on the monopole strength distribution in the double magic nucleus 48Ca. Using the same set of parameters, we describe available experimental data [9,10]. The effects of the phonon-phonon coupling leads to a redistribution of the main monopole strength to lower energy states and also to higher energy tail [11].
This work was supported by the Russian Science Foundation (Grant No. RSF-21-12-00061).

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9. K. Howard et al., Phys. Lett. B. 801, 135185 (2020).
10. S.D. Olorunfunmi et al., arXiv:2202.00722v1 [nucl-ex] 1 Feb 2022.
11. N.N. Arsenyev, and A.P. Severyukhin, in preparation.

Presentation Materials

arsenyev_nucleus2022.docx