Results from a Search for Dark Matter in the Complete LUX Exposure

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• The nature of dark matter remains one of the most significant unsolved problems in physics.
• Weakly Interacting Massive Particles (WIMPs) are a leading theoretical candidate for dark matter.
• Direct detection experiments aim to observe WIMP interactions with ordinary matter.

Purpose of the Study:

• To constrain the spin-independent WIMP-nucleon scattering cross section using a new dataset from the LUX experiment.
• To improve the sensitivity of WIMP detection limits, particularly for higher WIMP masses.

Main Methods:

• Utilized a 3.35x10^4 kg-day exposure from the Large Underground Xenon (LUX) experiment.
• Employed a dual-phase xenon time projection chamber with 250 kg of active mass.
• Operated the detector at the Sanford Underground Research Facility.

Main Results:

• No statistically significant excess of events consistent with WIMP nuclear recoils was observed.
• Excluded spin-independent WIMP-nucleon cross sections above 2.2x10^-46 cm^2 at 90% confidence level for a WIMP mass of 50 GeV/c^2.
• Combined analysis with previous LUX data strengthened the exclusion to 1.1x10^-46 cm^2 at 50 GeV/c^2.

Conclusions:

• The LUX experiment provides the most stringent limits to date on spin-independent WIMP-nucleon interactions.
• The results disfavor a significant portion of the parameter space predicted by popular WIMP models.
• Future dark matter direct detection experiments will build upon these sensitivities.