Search for double-beta decay of $$\mathrm {^{130}Te}$$ to the $$0^+$$ states of $$\mathrm {^{130}Xe}$$ with CUORE

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2021-07, Vol.81 (7), Article 567
• Main Authors: Adams, D. Q., Alduino, C., Alfonso, K., Avignone, F. T. III, Azzolini, O., Bari, G., Bellini, F., Benato, G., Biassoni, M., Branca, A., Brofferio, C., Bucci, C., Camilleri, J., Caminata, A., Campani, A., Canonica, L., Cao, X. G., Capelli, S., Cappelli, L., Cardani, L., Carniti, P., Casali, N., Celi, E., Chiesa, D., Clemenza, M., Copello, S., Cosmelli, C., Cremonesi, O., Creswick, R. J., D’Addabbo, A., Dafinei, I., Davis, C. J., Dell’Oro, S., Domizio, S. Di, Dompè, V., Fang, D. Q., Fantini, G., Faverzani, M., Ferri, E., Ferroni, F., Fiorini, E., Franceschi, M. A., Freedman, S. J., Fu, S. H., Fujikawa, B. K., Giachero, A., Gironi, L., Giuliani, A., Gorla, P., Gotti, C., Gutierrez, T. D., Han, K., Heeger, K. M., Huang, R. G., Huang, H. Z., Johnston, J., Keppel, G., Kolomensky, Yu. G., Ligi, C., Ma, L., Ma, Y. G., Marini, L., Maruyama, R. H., Mayer, D., Mei, Y., Moggi, N., Morganti, S., Napolitano, T., Nastasi, M., Nikkel, J., Nones, C., Norman, E. B., Nucciotti, A., Nutini, I., O’Donnell, T., Ouellet, J. L., Pagan, S., Pagliarone, C. E., Pagnanini, L., Pallavicini, M., Pattavina, L., Pavan, M., Pessina, G., Pettinacci, V., Pira, C., Pirro, S., Pozzi, S., Previtali, E., Puiu, A., Rosenfeld, C., Rusconi, C., Sakai, M., Sangiorgio, S., Schmidt, B., Scielzo, N. D., Sharma, V., Singh, V., Sisti, M., Speller, D., Surukuchi, P. T.
• Format: Article
• Language: English
• Subjects: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-021-09317-z

The CUORE experiment is a large bolometric array searching for the lepton number violating neutrino-less double beta decay ( $$0\nu \beta \beta $$ 0 ν β β ) in the isotope $$\mathrm {^{130}Te}$$ 130 Te . In this work we present the latest results on two searches for the double beta decay (DBD) of $$\mathrm {^{130}Te}$$ 130 Te to the first $$0^{+}_2$$ 0 2 + excited state of $$\mathrm {^{130}Xe}$$ 130 Xe : the $$0\nu \beta \beta $$ 0 ν β β decay and the Standard Model-allowed two-neutrinos double beta decay ( $$2\nu \beta \beta $$ 2 ν β β ). Both searches are based on a 372.5 kg $$\times $$ × yr TeO $$_2$$ 2 exposure. The de-excitation gamma rays emitted by the excited Xe nucleus in the final state yield a unique signature, which can be searched for with low background by studying coincident events in two or more bolometers. The closely packed arrangement of the CUORE crystals constitutes a significant advantage in this regard. The median limit setting sensitivities at 90% Credible Interval (C.I.) of the given searches were estimated as $$\mathrm {S^{0\nu }_{1/2} = 5.6 \times 10^{24} \, \mathrm {yr}}$$ S 1 / 2 0 ν = 5.6 × 10 24 yr for the $${0\nu \beta \beta }$$ 0 ν β β decay and $$\mathrm {S^{2\nu }_{1/2} = 2.1 \times 10^{24} \, \mathrm {yr}}$$ S 1 / 2 2 ν = 2.1 × 10 24 yr for the $${2\nu \beta \beta }$$ 2 ν β β decay. No significant evidence for either of the decay modes was observed and a Bayesian lower bound at $$90\%$$ 90 % C.I. on the decay half lives is obtained as: $$\mathrm {(T_{1/2})^{0\nu }_{0^+_2} > 5.9 \times 10^{24} \, \mathrm {yr}}$$ ( T 1 / 2 ) 0 2 + 0 ν > 5.9 × 10 24 yr for the $$0\nu \beta \beta $$ 0 ν β β mode and $$\mathrm {(T_{1/2})^{2\nu }_{0^+_2} > 1.3 \times 10^{24} \, \mathrm {yr}}$$ ( T 1 / 2 ) 0 2 + 2 ν > 1.3 × 10 24 yr for the $$2\nu \beta \beta $$ 2 ν β β mode. These represent the most stringent limits on the DBD of $$^{130}$$ 130 Te to excited states and improve by a factor $$\sim 5$$ ∼ 5 the previous results on this process.