München 2019 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 49: Structure and Dynamics of Nuclei IX

HK 49.5: Vortrag

Donnerstag, 21. März 2019, 15:15–15:30, HS 14

Yrast transition strengths in ¹¹⁶Te — •Christoph Fransen, Marcel Bast, Marcel Beckers, Thomas Braunroth, Alfred Dewald, Alina Goldkuhle, Jan Jolie, Julia Litzinger, and Claus Mueller-Gatermann — Institut für Kernphysik, Universität zu Köln

An anomalous behaviour of the B(E2,2₁⁺ → 0₁⁺) and B(E2,4₁⁺ → 2₁⁺) values was found in Sn isotopes below mid-shell. However, the puzzling B(E2;2₁⁺→ 0₁⁺) systematics around N=60 was understood very recently in state-of-the-art Monte-Carlo shell model calculations [1] by activating protons in the 1g_9/2 orbit and a second-order quantum phase transition from the moderately deformed phase to the pairing (seniority) phase that occurs around N=66. But a sharp drop of the B(E2,4₁⁺ → 2₁⁺) values below N=66 leading to unusual small B(E2;4₁⁺→ 2₁⁺)/B(E2;2₁⁺→ 0₁⁺) values is not understood so far. In neighboring Te isotopes a similar situation seems to be present, where especially data on B(E2;4₁⁺→ 2₁⁺) values are lacking that would allow a clear conclusion. In this framework ¹¹⁶Te₆₄ represents an interesting case as it is just at the edge of the shape transition observed in neighboring Sn isotopes as is also supported by experimental data on ^112,114Te. Therefore, we determined B(E2) values between the lowest states in ¹¹⁶Te from level lifetimes measured with the recoil distance Doppler-shift method. We will present these results and relate them both to the systematics along the Te isotopic chain and to the interpretation of the Sn isotopes.

[1] T. Togashi et al., Phys. Rev. Lett. 121, 062501 (2018)