Search for Neutrinoless Double-Beta Decay of Te 130 with CUORE-0

We report the results of a search for neutrinoless double-beta decay in a 9.8 kg yr exposure of 130Te using a bolometric detector array, CUORE-0. The characteristic detector energy resolution and background level in the region of interest are 5.1 0.3 keV FWHM and 0.058 0.004ðstatÞ 0.002ðsystÞcounts=ðkeV kg yrÞ, respectively. The median 90% C.L. lower-limit half-life sensitivity of the experiment is 2.9 × 1024 yr and surpasses the sensitivity of previous searches. We find no evidence for neutrinoless double-beta decay of 130Te and place a Bayesian lower bound on the decay half-life, T0ν1=2 > 2.7 × 1024 yr at 90% C.L. Combining CUORE-0 data with the 19.75 kg yr exposure of 130Te from the Cuoricino experiment we obtain T0ν1=2 > 4.0 × 1024 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, mββ < 270–760 meV.