Non-yrast low-spin states in the triaxially deformed nucleus 123Xe

The non-yrast states of 123Xe have been investigated with the reaction 123Te(3He, 3n) by means of in-beam γ-spectroscopy using a setup of 6 Compton-suppressed high-purity-germanium (HPGe) detectors. More than 130 new transitions establishing over 35 new levels were observed. γγ angular correlations were analyzed to assign spins and parities to the low-lying states, and to determine the multipole mixing ratios of the γ-transitions. With this method 9 spin and parity assignments were made and 19 multipole mixing ratios could be determined. Excitation energies of negative-parity states and the branching ratios of their decays are compared with predictions of the Rigid Triaxial Rotor plus Particle model (RTRP)