Deformation of the proton emitterCs113from electromagnetic transition and proton-emission rates

D Hodge,H Badran,C Scholey,J Uusitalo,P T Greenlees,P Papadakis,J Pakarinen,L Capponi,M J Taylor,M Sandzelius,R Julin,J Partanen,B S Nara Singh,D M Cullen,P Ruotsalainen,E Maglione,J Sarén,P Rahkila,T Braunroth,T Grahn,J Konki,J Sorri,O Nefodov,J F Smith,L S Ferreira,Sanna Stolze ,M Smoleń ,G O’neill ,Michael Mallaburn ,Oleksii Girka

doi:10.1103/physrevc.94.034321

Abstract

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.

Highlights

Proton emission can provide valuable nuclear-structure information and allow sensitive tests of theoretical nuclear models for proton-rich nuclei in the region beyond the drip line [1,2]
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 113Cs was best described as a deformed proton emitter, it is more firmly supported by the present measurement of the electromagnetic transition rate
Wave functions extracted from this model were fixed and used consistently in both proton emission codes based on the approaches discussed in Ref. [18] and standard electromagnetic transition-rate calculations based on Refs. [37,38]

Summary

INTRODUCTION

Proton emission can provide valuable nuclear-structure information and allow sensitive tests of theoretical nuclear models for proton-rich nuclei in the region beyond the drip line [1,2]. Further developments of that work allowed improved wave functions to be obtained using a nonadiabatic quasiparticle model [17,18,19] These nonadiabatic calculations have been used for 113Cs in the present work to allow for any non rigid-rotational components in the daughter nucleus, 112Xe. In order to validate the theoretical predictions of deformation in these nuclei, any experimental information on the deformation of the proton-emitting states in 113Cs, or even the states in the bands built upon them, is necessary. The lifetime has been interpreted within a new theoretical framework which considers both electromagnetic transition and proton emission rates using a common deformation and a common set of wave functions from a nonadiabatic quasiparticle model [17,18,19] This approach has demonstrated that 113Cs is best described as a deformed nucleus with a quadrupole deformation parameter, β2 = 0.22(6)

EXPERIMENTAL DETAILS

RESULTS

DISCUSSION

Predicted excitation energies of the states

Predicted proton-emission transition rates

Result from