Search of the neutrino-less double beta decay of $$^{82}$$ 82 Se into the excited states of $$^{82}$$ 82 Kr with CUPID-0

Abstract

Abstract The CUPID-0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95$$\%$$ % enriched in $$^{82}$$ 82 Se and two natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of $$^{82}$$ 82 Se into the 0$$_1^+$$ 1+ , 2$$_1^+$$ 1+ and 2$$_2^+$$ 2+ excited states of $$^{82}$$ 82 Kr with an exposure of 5.74 kg$$\cdot $$ · yr (2.24$$\times $$ × 10$$^{25}$$ 25 emitters$$\cdot $$ · yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: $$\varGamma $$ Γ ($$^{82}$$ 82 Se $$\rightarrow ^{82}$$ →82 Kr$$_{0_1^+}$$ 01+ )8.55$$\times $$ × 10$$^{-24}$$ -24 yr$$^{-1}$$ -1 , $$\varGamma $$ Γ ($$^{82}$$ 82 Se $$\rightarrow ^{82}$$ →82 Kr $$_{2_1^+}$$ 21+ )$$\,{<}\,6.25 \,{\times }\,10^{-24}$$ <6.25×10-24 yr$$^{-1}$$ -1 , $$\varGamma $$ Γ ($$^{82}$$ 82 Se $$\rightarrow ^{82}$$ →82 Kr$$_{2_2^+}$$ 22+ )8.25$$\times $$ × 10$$^{-24}$$ -24 yr$$^{-1}$$ -1 (90$$\%$$ % credible interval).