Münster 2017 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 32: Structure and Dynamics of Nuclei V

HK 32.4: Vortrag

Mittwoch, 29. März 2017, 17:45–18:00, F 33

Saturation of B(E2)-strength near mid-shell? Lifetimes of ^{174,176,178,180}Hf. — •Johannes Wiederhold¹, Ralph Kern¹, Volker Werner^1,4, Norbert Pietralla¹, Nicu Marginean², Raluca Marginean², Cristina R. Nita², Sorin Pascu², Dorel Bucurescu², Dan M. Filipescu², Nicoleta Florea², Dan G. Ghita², Constantin Mihai², Razvan Lica², Patrick Regan³, Robert Carroll³, Terver Daniel³, Laila Gurgi³, Ralitsa Ilieva^3,4, Nathan Cooper⁴, and Farheen Naqvi⁴ — ¹IKP, TU-Darmstadt — ²IFIN-HH, Bucharest — ³Physics Department at Surrey — ⁴Yale University

Deformed nuclei in the rare earth region should show a saturation of the B(E2;0₁⁺→2₁⁺)-transition strength near mid-shell. Recent measurements of lifetimes of W-isotopes show discrepancies to literature values and seem to maximize the B(E2)-strength off mid-shell. An analog investigation is done on Hf-isotopes. Several lifetimes of excited states of the even-even isotopes ^{174,176,178,180}Hf have been measured with fast electronic scintillation timing (FEST) using the same experimental setup to minimize systematic deviations among the values. Excited States were populated via Coulomb excitation (¹⁸⁰Hf) and via β⁺-decay following fusion-evaporation reactions (^174,176,178Hf) at the 9 MV tandem accelerator of the IFIN-HH near Bucharest. Obtained lifetimes of the Hf-isotopes will be presented. This work was supported by the DFG under Grants No. SFB 634 and No. SFB 1245, the U.S. DOE Grant No. DE-FG02-91ER40609 and the BMBF under the grant 05P15RDFN9 within the collaboration 05P15 NuSTAR R&D.