Search for double beta decay of ${}^{116}$Cd with enriched ${}^{116}$CdWO${}_4$ crystal scintillators (Aurora experiment)

Abstract

The Aurora experiment to investigate double beta decay of ${}^{116}$Cd with the help of 1.162 kg cadmium tungstate crystal scintillators enriched in ${}^{116}$Cd to 82\% is in progress at the Gran Sasso Underground Laboratory. The half-life of ${}^{116}$Cd relatively to the two neutrino double beta decay is measured with the highest up-to-date accuracy $T_{1/2}=(2.62\pm 0.14)\times 10^{19}$ yr. The sensitivity of the experiment to the neutrinoless double beta decay of ${}^{116}$Cd to the ground state of ${}^{116}$Sn is estimated as $T_{1/2}\ge 1.9\times 10^{23}$ yr at 90\% CL, which corresponds to the effective Majorana neutrino mass limit $⟨m_{\hat{I}}½⟩\le (1.2-1.8)$ eV. New limits are obtained for the double beta decay of ${}^{116}$Cd to the excited levels of ${}^{116}$Sn, and for the neutrinoless double beta decay with emission of majorons.

5 pages, 3 figures, 1 table, submitted as proceedings of the TAUP 2015 conference