Lifetime measurement of the ²⁶O g.s. at SAMURAI

The ground state of the neutron unbound nucleus ²⁶O is speculated to have a lifetime in the pico-second regime. In order to determine the decay lifetime of the ²⁶O ground state with high sensitivity and precision, a new method has been applied. The experiment was performed in December 2016 at the Superconducting Analyzer for MUlti-particle from Radio Isotope Beams (SAMURAI) at the Radioactive Isotope Beam Factory (RIBF) at RIKEN. A ²⁷F beam was produced in the fragment separator BigRIPS and impinged on a W/Pt target ²⁶O ²⁶O outside the target. Thus, the velocity difference between the decay neutrons and the fragment 1 O delivers a characteristic spectrum from which the lifetime can be extracted.