Discovery of the new proton emitter 144Tm

Evidence for the proton decay of Tm-144 was found in an experiment at the Recoil Mass Spectrometer at Oak Ridge National Laboratory. The Tm-144 events were found in the weak p5n channel of the fusion reaction using a Ni-58 beam at 340 MeV on a Mo-92 target. The observed proton decay energies are 1.70 MeV and 1.43 MeV and the half-life similar to 1.9 mu s. The decay properties suggest proton emission from the dominant pi h(11/2) part of the wave function and from the small pi f(7/2) admixture coupled to a quadrupole vibration.