Coulomb shift in two-center mirror systems

The so-called cluster structures appear in the excited states of light nuclear systems, and the structures have been extensively investigated in N = Z self-conjugate systems.

In the present report, we focus on a mirror system in non self-conjugate systems (N ≠ Z) and demonstrate that the Coulomb shift of the mirror systems is a new probe to catch the sign of the clustering phenomena. Here we discuss the Coulomb shift in the energy levels of the mirror systems, such as ¹⁸O = α + ¹⁴C and ¹⁸Ne = α + ¹⁴O. We have applied the orthogonality condition model (OCM) to these systems. The OCM calculation predicts that the Coulomb shift for the resonant 0⁺ states is prominently reduced in comparison to the shift for the low-lying bound states. This reduction is induced by the development of the α clustering. Therefore, this result strongly suggests that the Coulomb shift is new probe to identify the cluster degrees of freedom.

In this report, we will discuss the enhanced monopole transition, which is another probe to identify the cluster degrees of freedom in detail.