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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].
The random phase approximation (RPA) with the Skyrme-type energy-density functional (EDF) is the most widely used theoretical model for describing the ISGMR [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].
In the present report, we discuss 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 nuclei 40,48Ca and 208Pb. Using the same set of parameters, we describe available experimental data [7,8]. The effects of the phonon-phonon coupling (PPC) [9] lead to a redistribution of the main monopole strength to lower energy states and into higher energy tail [8,10]. In particular, the PPC predictions of the fine structure of the ISGMR in the Ca isotopes are in good agreement with the fine structure which is extracted from experimental data analysis [11].
The research was supported within the framework of the scientific program of the National Center for Physics and Mathematics, topic No. 6 "Nuclear and Radiation Physics" (stage 2023–2025).
[1] M.N. Harakeh and A. van der Woude, Giant Resonances (Clarendon Press, Oxford, 2001).
[2] Z.Z. Li, Y.F. Niu, and G. Colò, Phys. Rev. Lett. 131, 082501 (2023).
[3] N.N. Arsenyev, and A.P. Severyukhin, Universe. 7, 145 (2021).
[4] H.A. Bethe, Rev. Mod. Phys. 62, 801 (1990).
[5] N.K. Glendenning, Phys. Rev. Lett. 57, 1120 (1986).
[6] N.N. Arsenyev, A.P.Severyukhin, R.G. Nazmitdinov, JETP Letters, 118, 718 (2023).
[7] S.D. Olorunfunmi et al., Phys. Rev. C. 105, 054319 (2022).
[8] A. Bahini et al., Phys. Rev. C. 109, 014325 (2024).
[9] A.P. Severyukhin, V.V. Voronov, and N.V. Giai, Eur. Phys. Jour. A. 22, 397 (2004).
[10] N.N. Arsenyev, and A.P. Severyukhin, Phys. At. Nucl. 85, 912 (2022); 86, 465 (2023).
[11] S.D. Olorunfunmi et al., in preparation.
| Section | Nuclear structure: theory and experiment |
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