Three-quasineutron γ-band in ¹²⁷Xe

Abstract Structures of negative parity multi-quasiparticle states in 127 Xe have been investigated through in-beam γ -ray spectroscopy. Excited states were populated via the 122 Sn( 9 Be, 4n γ ) 127 Xe fusion-evaporation reaction at E beam = 48 MeV. Two new negative parity bands have been identified and their structures have been discussed using the triaxial projected shell model (TPSM) approach. One of the bands is established above the I π = 27/2 − state at 3702 keV and based on the experimental inferences and TPSM results, this band is interpreted as a γ -band built on a three-quasineutron configuration. The second sequence, found above I π = 31/2 − state at 4848 keV, is proposed to have a two-proton aligned configuration ( ν h 11 / 2 ⨂ π h 11 / 2 2 ), considering the properties of this band with the neighbouring isotopes. The analysis of the TPSM wave function substantiates the proposed interpretation of this band.