Search for Neutrinoless Double-Beta Decay of ${}^{130}$Te with CUORE-0

Abstract

We report the results of a search for neutrinoless double-beta decay in a 9.8~kg$\cdot$yr exposure of ${}^{130}$Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are $5.1\pm 0.3\mathrm{keV}$ FWHM and $0.058\pm 0.004(stat.)\pm 0.002(syst.)$~counts/(keV$\cdot$kg$\cdot$yr), respectively. The median 90%~C.L. lower-limit sensitivity of the experiment is $2.9\times 10^{24}\mathrm{yr}$ and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of ${}^{130}$Te and place a Bayesian lower bound on the decay half-life, $T_{1/2}^{0\hat{I}½}>$~$2.7\times 10^{24}\mathrm{yr}$ at 90%~C.L. Combining CUORE-0 data with the 19.75~kg$\cdot$yr exposure of ${}^{130}$Te from the Cuoricino experiment we obtain $T_{1/2}^{0\hat{I}½}>4.0\times 10^{24}\mathrm{yr}$ at 90%~C.L.~(Bayesian), the most stringent limit to date on this half-life. Using a range of nuclear matrix element estimates we interpret this as a limit on the effective Majorana neutrino mass, $m_{{\hat{I}}^2{\hat{I}}^2}<270$ -- $760\mathrm{meV}$.

6 pages, 5 figures, updated version as published in PRL