V. Tretyak - Final results of the Aurora experiment to study double beta decay of 116Cd with enriched 116CdWO4 crystal scintillators

by Volodymyr Tretyak (INR Kiev, Ukraine)

Pontecorvo room (LNGS)

Pontecorvo room



The double beta decay of 116Cd has been investigated with the help of radiopure enriched 116CdWO4 crystal scintillators (1.162 kg) at the Gran Sasso underground laboratory. The half-life of 116Cd relative to the two neutrino double beta decay to the ground state of 116Sn was measured with the highest up-to-date accuracy as T1/2=(2.63±0.11)´1019 yr. A new improved limit on the neutrinoless double beta decay of 116Cd to the ground state of 116Sn was set as T1/2 > 2.2´1023 yr at 90% C.L., which is the most stringent known restriction for this isotope (corresponds to the effective Majorana neutrino mass limit in the range of 1.0 - 1.7 eV, depending on the nuclear matrix elements used in the estimations). New improved half-life limits for double beta decay with majoron(s) emission, Lorentz-violating decay, and transitions to excited states of 116Sn were set at the level of > 1020 – 1022 yr. New limits for the hypothetical lepton-number violating parameters (right-handed current admixtures in weak interaction, the effective majoron-neutrino coupling constants, R-parity violating parameter, Lorentz-violating parameter, heavy neutrino mass) were set.
Volodymyr Tretyak
Institute for Nuclear Research
Kyiv, Ukraine