Three-quasineutron γ-band in ¹²⁷Xe

Abstract

Structures of negative parity multi-quasiparticle states in 127Xe have been investigated through in-beam γ-ray spectroscopy. Excited states were populated via 122Sn(9Be, 4nγ)127Xe fusion-evaporation reaction at Ebeam = 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 Iπ = 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 Iπ = 31/2- state at 4848 keV, is proposed to have a two-proton aligned configuration (νh11/2 ⊗ πh11/2 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.