Exotic decay of Cs 115

The detailed study of the β+/EC decay of the very neutron-deficient and alpha-unbound nucleus Cs115 is presented. The measurement was performed at the ISOLDE, CERN where delayed charged particles and γ rays were detected. The observed delayed γ rays are in agreement with the previously reported characteristics γ rays of Xe115. Based on the experimental observations, the tentative ground-state spin of Cs115 is suggested to be 7/2+ or 9/2+. Furthermore, the measured decay branching ratio of delayed protons exceeds the previously reported value. Additionally, new delayed α-branching ratio and several reconstructed proton and α-unbound excited states of Xe115 are being reported for the first time. The properties of proton-unbound states at excitation energies from 3.9-7.9 MeV have been obtained by fitting the delayed proton spectrum via the Bayesian method. The measured lifetimes of these proton-unbound states are in the order of zeptoseconds.