First Results from CUORE: A Search for Lepton Number Violation via 0 nu ss ss Decay of Te-130

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: Te-130 neutrinoless double-beta decay. Examining a total TeO2 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-1/2(0 nu) (Te-130) > 1.3 x 10(25) yr (90% C.L.); the median statistical sensitivity of this search is 7.0 x 10(24) yr. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T-1/2(0 nu) (Te-130) > 1.5 x 10(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(ss ss) < (110 - 520) meV, where the range reflects the nuclear matrix element estimates employed.