Alternative Interpretation of Sharply Rising E0 Strengths in Transitional Regions

It is shown that strong 0⁺₂→0⁺₁ E0 transitions provide a clear signature of phase transitional behavior in finite nuclei. Calculations using the interacting-boson approximation (IBA) show that these transition strengths exhibit a dramatic and robust increase in spherical-deformed shape transition regions, that this rise matches well the existing data, that the predictions of these E0 transitions remain large in deformed nuclei, that they arise from the specific d-boson coherence in the wave functions, and do not necessarily require the explicit mixing of normal and intruder configurations from different IBA spaces.