Two-neutrino 2β decay of 116Cd and new half-life limits on 2β decay of 180W and 186W

Abstract Studies of the 2 β decay of 116 Cd, 180 W and 186 W have been performed in the Solotvina Underground Laboratory with the help of the super-low background 116 CdWO 4 crystal scintillators. The half-life value of the two-neutrino 2 β decay of 116 Cd has been revised as T 1/2 2ν =2.9±0.1( stat ) −0.3 +0.4 ( syst )×10 19 yr . Besides, the new half-live limits on different modes of this process have been established for two natural tungsten isotopes, in particular, T 1/2 ⩾1.0 (1.6)×10 21  yr at 90% (68%) C.L. for the neutrinoless 2 β decay of 186 W to the ground (0 + ) and first excited (2 + ) level of 186 Os.