LXXIV International conference Nucleus-2024: Fundamental problems and applications

ON THE STRENGTH DISTRIBUTION OF ISOSCALAR GIANT MONOPOLE RESONANCE IN MEDIUM-HEAVY SPHERICAL NUCLEI

3 Jul 2024, 09:30

20m

Blokhintsev Hall (BLTP)

Oral Nuclear structure: theory and experiment

Speaker

Mikhail Gorelik (Moscow Economic School)

Description

Being associated with breathing modes of high-energy nuclear excitations,the Isoscalar Giant Monopole Resonance (ISGMR) is the object of permanent experimental and theoretical studies [1, 2]. In studies of Ref. [2], the detailed theoretical description of ISGMR (together with L=1,2,3) isoscalar GRs) in medium-heavy closed-shell nuclei have been proposed within the semi-microscopic Particle-Hole Dispersive Optical Model (PHDOM). Although this model is not fully self-consistent, it demonstrates unique abilities in describing main characteristics (strength distribution, transition densities, probabilities of direct one-nucleon decay) of various GRs in the above-mentioned nuclei (Refs. [2, 3] and references therein). These abilities appear due to specific features of PHDOM, in which the main relaxation modes of collective (p-h)-type states associated with GRs (Landau damping, coupling these states to single-particle continuum and to many-quasiparticle configurations (the spreading effect)) are together taken into account. In particular, these modes are the main contributors to formation of the GR total width.

In this report, we present a comparison of the strength functions of ISGMR in 48Ca, 90Zr, and 208Pb evaluated within PHDOM [2] and cRPA (continuum-random-phase approximation) with the strength distributions deduced from an analysis of the respective (α,α’)-reaction cross sections [4, 5, 6]. In neglecting contribution of pair correlations to formation of the ISGMR strength function (this effect is expected to be weak), a similar comparison is done for open-shell nuclei 58Ni and 120Sn (experimental data are taken from Refs. [5, 6]). As a result, one can conclude that due to the above-mentioned features of PHDOM it is possible within this model to describe reasonably the strength distribution of ISGMR in medium-heavy spherical nuclei. Respective results of other theoretical approaches are also discussed.

1. Garg, U. and Colo, G., Progr. Part. Nucl. Phys., 101, 55 (2018).
2. Gorelik, M. L. and Shlomo, S. and Tulupov, B. A. and Urin, M. H., Phys. Rev. C, 103, 034302 (2021), Phys. Rev. C, 108, 014328 (2023).
3. Bondarenko, V. I. and Urin, M. H., Phys. Rev. C, 106, 024331 (2022), Phys. Rev. C, 109 (2024) (in press, https://arxiv.org/abs/2309.17173 ).
4. Olorunfunmi, S. D. and Neveling, R. and Carter, J. and von Neumann-Cosel, P. and Usman, I. T. and Adsley, P. and Bahini, A. and Baloyi, L. P. L. and Brummer, J. W. and Donaldson, L. M. and Jivan, H. and Kheswa, N. Y. and Li, K. C. W. and Marin-Lambarri, D. J. and Molema, P. T. and Moodley, C. S. and O'Neill, G. G. and Papka, P. and Pellegri, L. and Pesudo, V. and Sideras-Haddad, E. and Smit, F. D. and Steyn, G. F. and Avaa, A. A. and Diel, F. and Dunkel, F. and Jones, P. and Karayonchev, V., Phys. Rev. C, 105, 054319 (2022).
5. Bahini, A. and Neveling, R. and von Neumann-Cosel, P. and Carter, J. and Usman, I. T. and Adsley, P. and Botha, N. and Brummer, J. W. and Donaldson, L. M. and Jongile, S. and Khumalo, T. C. and Latif, M. B. and Li, K. C. W. and Mabika, P. Z. and Molema, P. T. and Moodley, C. S. and Olorunfunmi, S. D. and Papka, P. and Pellegri, L. and Rebeiro, B. and Sideras-Haddad, E. and Smit, F. D. and Triambak, S. and Wiedeking, M. and van Zyl, J. J., Phys. Rev. C, 107, 034312 (2023).
6. Bahini, A. and von Neumann-Cosel, P. and Carter, J. and Usman, I. T. and Arsenyev, N. N. and Severyukhin, A. P. and Litvinova, E. and Fearick, R. W. and Neveling, R. and Adsley, P. and Botha, N. and Brummer, J. W. and Donaldson, L. M. and Jongile, S. and Khumalo, T. C. and Latif, M. B. and Li, K. C. W. and Mabika, P. Z. and Molema, P. T. and Moodley, C. S. and Olorunfunmi, S. D. and Papka, P. and Pellegri, L. and Rebeiro, B. and Sideras-Haddad, E. and Smit, F. D. and Triambak, S. and Wiedeking, M. and van Zyl, J. J., Phys. Rev. C, 109, 014325 (2024).