Rarest alpha and beta decays

by V.I. Tretyak (Institute for Nuclear Research, Kyiv, Ukraine)

Monday 18 Apr 2016, 14:00 → 16:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

Current status of experimental searches for rare alpha and beta decays is reviewed. Several interesting observations of alpha and beta decays, previously unseen due to big half lives (1015 – 1020 yr), have been achieved during last years thanks to improvements in experimental techniques and underground location of experiments that allows to suppress backgrounds. In particular, the list includes first observations of alpha decays of 151Eu, 180W (both to the ground state of daughter nuclei), 190Pt (to excited daughter state), 209Bi (to the ground and excited daughter states). Isotope 209Bi has the longest known half life of T1/2 ~ 1019 yr. Beta decay of 115In to the first excited state of 115Sn (Eexc=497.334 keV), recently observed at the first time, has the Qβ value of only 155±24 eV, which is the lowest Qβ value known to-date. Searches and investigations of other rare α and β decays (48Ca, 50V, 96Zr,! 113Cd, 123Te, 178m2Hf, 180mTa and others) are also discussed.