2022

Auranen, K.; Briscoe, A. D.; Ferreira, L. S.; Grahn, T.; Greenlees, P. T.; Herzáň, A.; Illana, A.; Joss, D. T.; Joukainen, H.; Julin, R.; Jutila, H.; Leino, M.; Louko, J.; Luoma, M.; Maglione, E.; Ojala, J.; Page, R. D.; Pakarinen, J.; Rahkila, P.; Romero, J.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Tolosa-Delgado, A.; Uusitalo, J.; Zimba, G.

Using the fusion-evaporation reaction 96Ru(58Ni,p4n)149Lu and the MARA vacuum-mode recoil separator, a new proton-emitting isotope 149Lu has been identified. The measured decay Q value of 1920(20) keV is the highest measured for a ground-state proton decay, and it naturally leads to the shortest directly measured half-life of 450+170−100 ns for a ground-state proton emitter. The decay rate is consistent with lp=5 emission, suggesting a dominant πh11/2 component for the wave function of the proton-emitting state. Through nonadiabatic quasiparticle calculations it was concluded that 149Lu is the most oblate deformed proton emitter observed to date.