Determination of the B(E3, 0+ → 3−)-excitation strength in octupole-correlated nuclei near A ≈ 224 by the means of Coulomb excitation at REX-ISOLDE

The IS475 collaboration conducted Coulomb-excitation experiments with postaccelerated radioactive ²²⁰Rn and ²²⁴Ra beams at the REX-ISOLDE facility. The beam particles (E_beam ≈ 2.83 MeV/u) were Coulomb excited using ⁶⁰Ni, ¹¹⁴Cd, and ¹²⁰Sn scattering targets. De-excitation γ-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured γ-ray yields. The extracted 3⁻||Ê3||0⁺ matrix element allows for the conclusion that, while ²²⁰Rn represents an octupole vibrational system, ²²⁴Ra has already substantial octupole correlations in its ground state. An observation that has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.