Improved Limit on Neutrinoless Double-Beta Decay in 130Te with CUORE

We report new results from the search for neutrinoless double-beta decay in Te-130 with the CUORE detector. This search benefits from a fourfold increase in exposure, lower trigger thresholds, and analysis improvements relative to our previous results. We observe a background of (1.38 +/- 0.07) x 10(-2) counts/(keV kg yr)) in the 0v beta beta decay region of interest and, with a total exposure of 372.5 kg yr, we attain a median exclusion sensitivity of 1.7 x 10(25) yr. We find no evidence for 0v beta beta decay and set a 90% credibility interval Bayesian lower limit of 3.2 x 10(25) yr on the Te-130 half-life for this process. In the hypothesis that 0v beta beta decay is mediated by light Majorana neutrinos, this results in an upper limit on the effective Majorana mass of 75-350 meV, depending on the nuclear matrix elements used.