학술논문

Search for Double-Beta Decay of $\mathrm{^{130}Te}$ to the $0^+$ States of $\mathrm{^{130}Xe}$ with CUORE
Document Type
article
Source
Subject
nucl-ex
Language
Abstract
The CUORE experiment is a large bolometric array searching for the leptonnumber violating neutrino-less double beta decay ($0u\beta\beta$) in theisotope $\mathrm{^{130}Te}$. In this work we present the latest results on twosearches for the double beta decay (DBD) of $\mathrm{^{130}Te}$ to the first$0^{+}_2$ excited state of $\mathrm{^{130}Xe}$: the $0u\beta\beta$ decay andthe Standard Model-allowed two-neutrinos double beta decay ($2u\beta\beta$).Both searches are based on a 372.5 kg$\times$yr TeO$_2$ exposure. Thede-excitation gamma rays emitted by the excited Xe nucleus in the final stateyield a unique signature, which can be searched for with low background bystudying coincident events in two or more bolometers. The closely packedarrangement of the CUORE crystals constitutes a significant advantage in thisregard. The median limit setting sensitivities at 90\% Credible Interval (C.I.)of the given searches were estimated as $\mathrm{S^{0u}_{1/2} = 5.6 \times10^{24} \: \mathrm{yr}}$ for the ${0u\beta\beta}$ decay and$\mathrm{S^{2u}_{1/2} = 2.1 \times 10^{24} \: \mathrm{yr}}$ for the${2u\beta\beta}$ decay. No significant evidence for either of the decay modeswas observed and a Bayesian lower bound at $90\%$ C.I. on the decay half livesis obtained as: $\mathrm{(T_{1/2})^{0u}_{0^+_2} > 5.9 \times 10^{24} \:\mathrm{yr}}$ for the $0u\beta\beta$ mode and$\mathrm{(T_{1/2})^{2u}_{0^+_2} > 1.3 \times 10^{24} \: \mathrm{yr}}$ for the$2u\beta\beta$ mode. These represent the most stringent limits on the DBD of$^{130}$Te to excited states and improve by a factor $\sim5$ the previousresults on this process.