E0 transition strengths from X(5) to the rigid rotor

Relative and absolute E0 transition strengths [ρ² (E0)] on the transitional path between the X(5) solution and the rigid rotor limit have been evaluated [1] within the framework of the Confined β-Soft (CBS) rotor model. Relative E0 transition strengths between the β-vibrational band and the ground state band decrease with increasing angular momentum for a given potential stiffness. The Z-independent quantity X ∝ ρ²(E0; 0⁺₂ → 0⁺₁)/B(E2; 0⁺₁ → 2⁺₁) has been traced between X(5) and the rigid rotor. It reaches the value 4β²M at the rigid rotor limit, as previously derived by Rasmussen. A new Inter-Band E0 − E2 correlation observable Y ∝ ρ²(E0; 0⁺₂ → 0⁺₁)/B(E2; 0⁺₂ → 2⁺₁)² has be en proposed, which is independent on the absolute nuclear deformation and solely depends on the nuclear stiffness. Available data for X and Y are in satisfactory agreement with the CBS model.