Investigation into the $B(E2)$ anomaly in $^{144}\mathrm{Nd}$ using Coulomb excitation

Investigation into the $B (E 2)$ anomaly in ${}^{144}{Nd}$ using Coulomb excitation

C. R. Fitzpatrick, V. Werner, R. F. Casten, E. Williams, H. Ai, C. W. Beausang, R. B. Cakirli, G. Gürdal, A. Heinz, E. A. McCutchan, D. A. Meyer, E. Novitski, J. Qian, and R. Winkler

Phys. Rev. C 78, 034309 – Published 16 September 2008

Abstract

The ratio of $B (E 2)$ strengths between the lowest lying members of the ground state band in ${}^{144}{Nd}$ , $B_{4 / 2} = B (E 2; 4_{1}^{+} \to 2_{1}^{+}) / B (E 2; 2_{1}^{+} \to 0_{1}^{+})$ , which is used to quantify collectivity in nonmagic nuclei, has been remeasured by means of Coulomb excitation. Ambiguities in literature values for this ratio have been resolved. The results are discussed in terms of the interplay of collective and single-particle degrees of freedom, and in the context of the formation of collective structures in the $A = 140$ mass region, and more generally near (sub)shell closures. In addition, the $B_{4 / 2}$ ratio of ${}^{148}{Sm}$ has been remeasured, and the quadrupole moment of the $4_{1}^{+}$ state is found to be on the order of $1 e b$ .