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.