Search for Electron-Capture Delayed Fission in the New Isotope 244Md

The electron-capture decay followed by a prompt fission process was searched for in the hitherto unknown most neutron-deficient Md isotope with mass number 244. Alpha decay with α -particle energies of 8.73–8.86 MeV and with a half-life of ... s was assigned to 244Md. No fission event with a similar half-life potentially originating from spontaneous fissioning of the short-lived electron-capture decay daughter 244Fm was observed, which results in an upper limit of 0.14 for the electron-capture branching of 244Md. Two groups of fission events with half-lives of ... ms and ... ms were observed. The ... ms activity was assigned to originate from the decay of 245Md. The origin of eight fission events resulting in a half-life of ms could not be unambiguously identified within the present data while the possible explanation has to invoke previously unseen physics cases. (ProQuest: ... denotes formulae omited.).