States in191Osobserved with the192Os(p,

Partial Dynamical Symmetry and the Phonon Structure of Cadmium Isotopes

“…have been shown to be unsatisfactory [2,3]. This has led to the conclusion that the normal-intruder strong-mixing scenario needs to be rejected, and have raised serious questions on the appropriateness of the multi-phonon interpretation [2,3]. In what follows, we consider a possible explanation for the "Cd problem", based on U(5) partial dynamical symmetry (PDS).…”

“…The cadmium isotopes since long have been considered as archetypal examples of spherical vibrators, manifesting the U(5) dynamical symmetry (DS) [1]. Recent studies, however, have cast doubt on the validity of this description [2,3]. In the present contribution, we address this question from a symmetry-oriented perspective, focusing on 110 Cd [4].…”

“…The U(5)-DS limit of the interacting boson model (IBM) [1], corresponds to the chain of nested algebras: U(6) ⊃ U(5) ⊃ SO(5) ⊃ SO (3). The basis states |[N ], n d , τ, n ∆ , L have quantum numbers which are the labels of irreducible representations of the algebras in the chain.…”

“…(a) Experimental spectrum and representative E2 rates[3,5] (in W.u.) of normal and intruder levels (0 + 2 , in 110 Cd.…”

“…for E2 transitions from normal levels in 110 Cd. The experimental (EXP) values are taken from[3,5]. The U(5)-DS [U(5)-PDS-CM] values are obtained for an E2 operator e BQ [e , whereQ = d † s + s †d andQ (N ) denotes its projection onto the [N ] boson space.…”