  We report constraints on spin-independent weakly interacting massive particle
(WIMP)-nucleon scattering using a 3.35e4 kg-day exposure of the Large
Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber
with 250 kg of active mass is operated at the Sanford Underground Research
Facility under Lead, South Dakota (USA). With roughly fourfold improvement in
sensitivity for high WIMP masses relative to our previous results, this search
yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV/c^2,
WIMP-nucleon spin-independent cross sections above 2.2e-46 cm^2 are excluded at
the 90% confidence level. When combined with the previously reported LUX
exposure, this exclusion strengthens to 1.1e-46 cm^2 at 50 GeV/c^2.

Cosmology and Nongalactic Astrophysics;Instrumentation and Methods for Astrophysics;High Energy Physics - Experiment;Instrumentation and Detectors