Lifetime measurement of excited states in $^{144}\mathrm{Ce}$: Enhanced $E1$ strengths in a candidate for octupole deformation

Lifetime measurement of excited states in ${}^{144}{Ce}$ : Enhanced $E 1$ strengths in a candidate for octupole deformation

M. Beckers, C. Müller-Gatermann, A. Blazhev, T. Braunroth, A. Dewald, C. Fransen, A. Goldkuhle, L. Kornwebel, J. Litzinger, F. von Spee, and K.-O. Zell

Phys. Rev. C 102, 014324 – Published 28 July 2020

Abstract

A lifetime measurement of excited states in ${}^{144}{Ce}$ using the ${}^{142}{Ce} ({}^{18}O, {}^{16}O)$ reaction with a beam energy of 67 MeV and the recoil distance Doppler-shift method was performed at the Cologne FN Tandem accelerator. Lifetimes of the three lowest yrast states in ${}^{144}{Ce}$ have been measured as well as for the $3_{1}^{-}$ state and an effective lifetime of the $4_{2}^{+}$ state. Reduced $E 2$ transition strengths determined using these results have been compared to predictions from recent shell-model calculations. From the interband transitions reduced $E 1$ strengths could be determined, which are strongly enhanced.