Signatures of triaxiality in low-spin spectra of ⁸⁶Ge

Low-spin states of neutron-rich ⁸⁴,⁸⁶,⁸⁸Ge were measured by in-flight γ-ray spectroscopy at 270 MeV/u at the RIKEN-RIBF facility. The exotic beams have been produced by primary ²³⁸U 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 γ radiation was detected by the NaI-array DALI2. De-excitations from the 6₁⁺, 4₁,₂⁺ , and 2₁,₂⁺ states of ⁸⁴,⁸⁶Ge and 4₁⁺ and 2₁,₂⁺ states of ⁸⁸Ge were observed. The data are compared to state-of-the-art shell model and beyond-mean-field calculations. Furthermore, a candidate for a 3₁⁺ state of ⁸⁶Ge was identified. This state plays a key role in the discussion of ground-state triaxiality of ⁸⁶Ge, along with other features of the low-energy level scheme. This work was published in [1]