Bonn 2020 – wissenschaftliches Programm
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HK 45.1: Gruppenbericht
Donnerstag, 2. April 2020, 14:00–14:30, J-HS E
High-spin structures of transitional Xe and Ba nuclei in the 50 ≤ Z, N ≤ 82 region — •L. Kaya1, A. Vogt1, P. Reiter1, M. Siciliano2,3, and A. Gargano4 — 1IKP, Universität zu Köln — 2INFN - LNL, Italy — 3INFN Padova, Italy — 4INFN Napoli, Italy
The 50 ≤ Z, N ≤ 82 region is a fertile testing ground for the predictions of modern shell-model calculations. Xe and Ba nuclei with A ≈ 135 form an important link in the smooth evolution from spherical to deformed shapes and were investigated after multinucleon-transfer employing the γ-ray tracking array AGATA coupled to the mass spectrometer PRISMA and in complementary fusion-evaporation reactions employing the HORUS γ-ray array at the University of Cologne. Pronounced proton and neutron alignments in the yrast bands of 131Xe and 134Ba were identified. The discoveries of Jπ=19/2+ and Jπ=23/2+ isomers in 133Ba, 133Xe and 135Ba are closing gaps in the systematics along the N=77 and N=79 isotones towards the proton subshell-closure at Z=64. Exploiting angular-correlation investigations, the ground-state band in 136Ba was found to be interrupted by negative-parity states only a few hundred keV above the Jπ= 10(+) isomer. Results on the first spectroscopy of high-spin states above the Jπ=8− isomeric bandhead in the odd-odd isotope 130I are presented. Large-scale shell-model calculations employing the GCN50:82, SN100PN, PQM130, and a realistic effective interactions reproduce the experimental findings and provide guidance to the interpretation of the observed high-spin features. Supported by the German BMBF (05P15PKFN9 TP1, 05P18PKFN9 TP1) and ENSAR-TNA03.