Journal Article

GSI-2026-00246

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png First Measurement of the Quadrupole Moment of the $2_{1}^{+}$ State in $^{110}Sn $

Cederkall, J. (Corresponding author) ; Fahlander, C. ; Golubev, P. ; Knyazev, A. ; Iwanicki, J. ; Wrzosek-Lipska, K. ; Blazhev, A. ; Reiter, P. ; Rosiak, D. ; Seidlitz, M. ; Warr, N. ; Butler, P. A. ; Gaffney, L. P. ; Berry, T. ; Cox, D. M. ; Pakarinen, J. ; Kröll, T. ; Henrich, C. ; Schilling, M. ; Stahl, C. ; von Schmid, M. ; Rainovski, G. ; Berger, C. ; Berner, C. ; Gernhäuser, R. ; Illana, A. ; De Witte, H. ; Górska, M.GSI* ; Habermann, T.GSI* ; Saha, S.GSI* ; de Angelis, G. ; Borge, M. J. G. ; Tengblad, O. ; Otsuka, T. ; Tsunoda, Y.

2025
APS College Park, Md.

Please use a persistent id in citations: doi:10.1103/7ysn-8y1w  doi:10.15120/GSI-2026-00246

Abstract: The Sn isotopic chain, exhibiting double shell closures at 100 Sn and 132 Sn , is a key testing ground for theoretical models of the atomic nucleus. It was originally predicted that the transitional matrix elements between the first 2+ state and the 0+ ground state for the even-even isotopes in this chain should show a simple dependence on the neutron number. This prediction was, however, disproven experimentally in some of the first experiments with postaccelerated radioactive beams, a situation that has remained unresolved ever since. Subsequent theoretical work has suggested that the explanation can be found in proton excitations across the 𝑍 =50 shell gap, with an accompanying experimental signature that the first excited 2+ state in 110 Sn should have a distinct oblate shape. In this Letter, we present the first measurements of the spectroscopic quadrupole moment of the 2+1 state, 𝐵⁡(𝐸⁢2;4+1→2+1) and 𝐵⁡(𝐸⁢2;4+2→2+1) values for 110 Sn , as well as the 𝐵⁡(𝐸⁢2;2+1→0+1) value with significantly improved precision compared to previous results. From the same experiment, half-lives of the 2+1 and 4+1 states were measured using the Doppler shift attenuation method. Our combined result, 𝑄⁡(2+1)=20⁢(8)  efm2 for 110 Sn , is the largest positive value known among the Sn isotopes, indicating an oblate shape of the state by more than 2⁢𝜎. Comparison of the 𝐸⁢2 transition strengths and quadrupole moments with recent shell model calculations are presented.

Note: Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license.

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Contributing Institute(s):

1. Kernspektroskopie (KSP)

Research Program(s):

1. 612 - Cosmic Matter in the Laboratory (POF4-612) (POF4-612)
2. 05P21PKCI1 - Verbundprojekt 05P2021 - ISOLDE: Kernstruktur fernab des Tales der Stabilität: Experimente mit nachbeschleunigten und gestoppten radioaktiven Ionenstrahlen bei ISOLDE (BMBF-05P21PKCI1) (BMBF-05P21PKCI1)
3. 05P21RDCI2 - Verbundprojekt 05P2021 - ISOLDE: Kernstrukturuntersuchungen mit MINIBALL bei ISOLDE (BMBF-05P21RDCI2) (BMBF-05P21RDCI2)
4. EURO-LABS - EUROpean Laboratories for Accelerator Based Science (101057511) (101057511)

Experiment(s):

1. External experiment at external facility/ no experiment at GSI (other)

Appears in the scientific report 2025

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; ; ; Clarivate Analytics Master Journal List ; Current Contents - Electronics and Telecommunications Collection ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; Nationallizenz ; SCOAP3 sponsored Journal ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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