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HK: Fachverband Physik der Hadronen und Kerne
HK 40: Structure and Dynamics of Nuclei X
HK 40.2: Talk
Thursday, March 13, 2025, 14:30–14:45, HS 2 Physik
Probing a sudden drop of collectivity at 170,172W — •K. E. Ide1, V. Werner1, R. Abels2, U. Ahmed1, D. Bittner2, T. Biesenbach2, A. Blazhev2, A. Esmaylzadeh2, C. Fransen2, J. Jolie2, H. Kleis2, C. -D. Lakenbrink2, M. Ley2, H. Mayr1, M. Müllenmeister2, C. M. Nickel1, R. Novak2, A. Pfeil2, N. Pietralla1, J. Roob2, F. von Spee2, T. Stetz1, T. Sültenfuß2, and R. Zidarova1 — 1IKP, TU Darmstadt — 2IKP, Uni Köln
Nuclear quadrupole collectivity is identified from enhanced E2 decay rates. The E2 decay strength of a state is inversely proportional to its lifetime. A sudden increase of the E2 strength of the 21+→01+ transition from N=96 (170W) to N=98 (172W) in the W isotopic chain is unexpected compared to the neighboring Hf isotopic chain. This discrepancy was previously investigated by lifetime measurements of yrast states of 170W [1]. Therefore, in this work we investigate yrast B(E2) values in 172W to learn about the structural evolution of the yrast band in comparison to 170W. The experiment was performed at the Cologne 10 MV FN-tandem accelerator facility and used the new CATHEDRAL spectrometer and a plunger device. The fast-timing method and the recoil distance Doppler-shift (RDDS) method are used complementary to determine the lifetimes of yrast states. First results will be presented and discussed together with the previous results on 170W and will be compared to the confined β-soft (CBS) rotor model.
[1] K. E. Ide et al., LNL report 2019 (2020).
*Supported by the BMBF under Grant No. 05P21RDCI2 and by DFG (GRK 2128, AccelencE).
Keywords: 172W; Cologne CATHEDRAL spectrometer; Cologne plunger device; Fast timing; RDDS