Shape coexistence in 132Ba

Rotational states have been populated in γ-soft 132Ba following the 122Sn(13C,3nγ) reaction. The ground state of this nucleus is predicted to possess maximal triaxiality γ∼-30 degree. Two ΔI=2 bands were established, based on quasineutron configurations with large negative γ deformations close to the collective oblate shape γ=-60 degree. The bandhead of one of these bands, associated with a [νh11/2]2 configuration, was found to be isomeric with a mean lifetime τ=12.5±0.3 ns. A third ΔI=2 band was observed, built on a two-quasiproton configuration with a near-prolate shape (γ∼0 degree). In addition, two ΔI=1 bands, built on mixed proton-neutron four-quasiparticle configurations with oblate shapes (γ∼-60 degree), were established