First Results from CUORE: A Search for Lepton Number Violation via 0νββ Decay of [superscript 130]Te

Abstract

The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-number-violating process: [superscript 130]Te neutrinoless double-beta decay. Examining a total TeO[subscript 2] exposure of 86.3 kg yr, characterized by an effective energy resolution of (7.7±0.5) keV FWHM and a background in the region of interest of (0.014±0.002) counts/(keV kg yr), we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of T[subscript 1/2][supsercript 0ν]([superscript 130]Te)>1.3×10[superscript 25] yr (90% C.L.); the median statistical sensitivity of this search is 7.0×10^{24} yr. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T[subscript 1/[superscript 0ν]([superscript 130]Te)>1.5×10[superscript 25] yr (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find m[subscript ββ]<(110-520) meV, where the range reflects the nuclear matrix element estimates employed.