Jun 13 – 17, 2022
Berkeley, CA
US/Pacific timezone

Discovery of the proton emitter 116La

Jun 15, 2022, 9:50 AM
Berkeley, CA

Berkeley, CA

Lawrence Berkeley National Laboratory
Oral Oral Presentations NS2022 Plenary


Bo Cederwall (KTH Royal Institute of Technology)


The discovery of the new proton emitter 116La, 23 neutrons away from stable 139La, will be reported. 116La nuclei were synthesised in the fusion-evaporation reactions at the University of Jyväskylä Accelerator Center and identified via their proton radioactivity using the MARA recoil mass spectrometer. Comparisons of the measured proton energy (E= 718 keV) and half-life (T1/2 = 50 +-22ms) with values calculated using microscopic nuclear barrier penetration theory indicate that the proton is emitted with an orbital angular momentum l=2 and that its emission probability is enhanced relative to its closest, less exotic, odd-even lanthanum isotope (117La) while the proton-emission Q-value is lower. We propose this unusual feature to be a signature for the presence of strong isovector neutron-proton pair correlations in this exotic, neutron deficient system. The observations of gamma decays from isomeric states in 116La and 117La will also be discussed.

Primary author

Bo Cederwall (KTH Royal Institute of Technology)


Wei et al. Zhang (KTH Royal Institute of Technology)

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