Seminar on low-energy nuclear physics

Date and Time: Tuesday, 16 May 2023, at 11:00 AM

Venue: Blokhintsev Hall (4th floor), Bogoliubov Laboratory of Theoretical Physics, online on Zoom

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Seminar topic: “Anomalous deformation dependence of moments of inertia in light deformed nuclei”

Speaker: Maria Mardyban

Abstract:

The deformation dependence of the moment of inertia J in light deformed nuclei ²⁴Mg and ²⁰Ne was investigated within macroscopic and macroscopic models. The microscopic study was performed within three cranking approaches for J (Inglis-Belyaev, Thouless-Valatin, adiabatic time-dependent Hartree-Fock) using Skyrme forces SVbas, SkM* and SLy6. The calculations cover a wide deformation range 0 < beta < 1.2. It was found that, at variance with macroscopic rigid-body and hydrodinamical estimations, there can exist a regime where J decreases with increasing the axial quadrupole deformation beta. This anomalous regime with dJ/d beta < 0 starts at about beta = 0.5 for ²⁴Mg and beta = 0.7 for ²⁰Ne, where the pairing already breaks down. The unusual trend of J is explained by a shell structure effect: specific evolution of few dominant particle-hole (1ph) configurations with beta. The analysis of experimental data for the ground-state rotational bands in ²⁴Mg and ²⁰Ne shows that such anomalous effect indeed can take place at low spins. For comparison, the dependence J (beta) in a standard medium-mass deformed nucleus ¹⁷⁰Hf is also inspected.