SMuK 2023 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 49: Structure and Dynamics of Nuclei IX

HK 49.5: Talk

Wednesday, March 22, 2023, 18:30–18:45, SCH/A118

Lifetime measurements of excited states in ⁵⁷Mn — •Hannah Kleis, Peter Reiter, Konrad Arnswald, Maximilian Droste, Andrey Blazhev, Ramona Burggraf, and Cristoph Fransen — Institut für Kernphysik, Universität zu Köln

Previously, the N=32 subshell closure was observed in the even-even Ca-, Ti-, and Cr-isotopes [1]. Adding more valence protons to the π (f_7/2) orbital reduces the shell gap at N=32 which vanishes completely at ₂₆⁵⁸Fe. Lifetime measurements in the odd-even ⁵⁷Mn nucleus were performed in order to close the gap between Z=24 and Z=26. Excited states of ⁵⁷Mn were populated via ⁵⁵Mn(¹⁸O, ¹⁶O)⁵⁷Mn two-neutron transfer reactions at a beam energy of 38 MeV employing the FN tandem accelerator at the University of Cologne. The Doppler-shift attenuation method is utilized to determine new lifetimes for the 11/2₁⁻ and 9/2₁⁻ states. The experimentally determined transition probabilities are confronted with results from the GXPF1A shell-model interaction along the Mn-isotopes. The experimental findings in ⁵⁷Mn are well reproduced by this interaction. The comparison of excitation energies and B(E2) strengths is extended to all odd-even nuclei between Ca and Ni with neutron numbers N=26 and N=36 in order to discuss the nature of the N=32 subshell closure.

[1] D. Steppenbeck et al., Nature 502, 7470 (2013)