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

The lifetime of the $(11/{2}^{+})$ state in the band above the proton-emitting $(3/{2}^{+})$ state in $^{113}\mathrm{Cs}$ has been measured to be $\ensuremath{\tau}=24(6)$ 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 $\ensuremath{\gamma}$-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 ${\ensuremath{\beta}}_{2}=0.22(6)$. This deformation is in agreement with the earlier proton emission studies which concluded that $^{113}\mathrm{Cs}$ was best described as a deformed proton emitter, however, it is now more firmly supported by the present measurement of the electromagnetic transition rate.