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HK: Fachverband Physik der Hadronen und Kerne

HK 26: Structure and Dynamics of Nuclei VII

HK 26.1: Gruppenbericht

Mittwoch, 12. März 2025, 14:00–14:30, HS 2 Physik

State-of-the-art nuclear structure studies with the recoil distance Doppler-shift technique — •Christoph Fransen¹, Andrey Blazhev¹, Felix Dunkel¹, Arwin Esmaylzadeh¹, Carina Heymer¹, Jan Jolie¹, Casper-David Lakenbrink¹, Claus Müller-Gatermann², Richard Novak¹, Franziskus von Spee¹, Nigel Warr¹, and Michael Weinert¹ — ¹Institut für Kernphysik, Universität zu Köln — ²Argonne National Laboratory, Illinios, USA

Absolute transition strengths between excited states yield fundamental information on nuclear structure and can be determined from level lifetimes. The recoil distance Doppler-shift (RDDS) technique employing so-called plunger devices provides a valuable method for the determination of lifetimes in the picosecond range and has been in the focus of our Cologne group since many years. Here, we will present our latest developments of the RDDS technique with respect to the application with very different experimental conditions and the required detection techniques to identify the reaction products. We will also discuss new results from RDDS measurements of our group in tellurium isotopes close to neutron midshell where the data give hints for shape coexistence. Furthermore, we will give an overview of our recent lifetime measurements in neutron-deficient nuclei in the A=170 region. In these nuclei, a B(E2) anomaly was already found for the lowest yrast states. Our new results allow to test different state-of-the-art nuclear model approaches aiming for an understanding of this anomaly also towards higher yrast states.

Supported by the DFG, grant No. FR 3276/3-1

Keywords: Level lifetimes; Plunger devices; Shape coexistence