Deformation of the proton emitter Cs 113 from electromagnetic transition and proton-emission rates

Abstract

The lifetime of the (11/2+) state in the band above the proton-emitting (3/2+) state in Cs113 has been measured to be τ=24(6) ps from a recoil-decay-tagged differential-plunger experiment. The measured lifetime was used to deduce the deformation of the states using wave functions from a nonadiabatic quasiparticle model to independently calculate both proton-emission and electromagnetic γ-ray transition rates as a function of deformation. The only quadrupole deformation, which was able to reproduce the experimental excitation energies of the states, the electromagnetic decay rate of the (11/2+) state and the proton-emission rate of the (3/2+) state, was found to be β2=0.22(6). This deformation is in agreement with the earlier proton emission studies which concluded that Cs113 was best described as a deformed proton emitter, however, it is now more firmly supported by the present measurement of the electromagnetic transition rate.