Low-spin states of neutron-rich Ge-84,Ge-86,Ge-88 were measured by in-flight gamma-ray spectroscopy at 270 MeV/u at the RIKEN-RIBF facility. The exotic beams have been produced by primary U-238 in-flight fission reactions and impinged on the MINOS device. MINOS combines a 10-cm long LH2 target with a Time Projection Chamber (TPC) to reconstruct the reaction vertices. The reactions were selected by the BigRIPS and the ZeroDegree spectrometers for the incoming and outgoing channels, respectively. Emitted gamma radiation was detected by the NaI-array DALI2. De-excitations from the 6(1)(+), 4(1,2)(+), and 2(1,2)(+) states of Ge-84,Ge- 86 and 4(1)(+) and 26 states of Ge-88 were observed. The data are compared to state-of-the-art shell model and beyond-mean-field calculations. Furthermore, a candidate for a 3(1)(+) state of Ge-86 was identified. This state plays a key role in the discussion of ground-state triaxiality of Ge-86, along with other features of the low-energy level scheme.

We acknowledge support from the German BMBF Grant Nos. 05P12RDFN1, 05P12RDFN8 and 05P15PKFNA, the ERC Grant No. MINOS258567, the Spanish Ministerio de Economıa y Competitividad under contracts FPA2014-57196-C5-4-P and FIS−2014−53434, the Vietnam Ministry of Science and Technology, as well as from the Science and Technology Facilities Council (STFC). We further thank GSI for providing computing facilities

7 pags., 4 figs. -- XXII International School on Nuclear Physics, Neutron Physics and Applications. -- Open Access funded by Creative Commons Atribution Licence 3.0

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