A Detailed Look at the First Results from the Large Underground Xenon (LUX) Dark Matter Experiment

TL;DR

LUX is the most sensitive direct dark matter detection experiment using a large xenon detector, setting new limits on WIMP interactions and providing detailed calibration and energy scale analysis.

Contribution

This paper presents the first results from LUX, including a new energy scale and calibration methods, and reports the most stringent limits on WIMP-nucleon cross-sections to date.

Findings

LUX achieved a limit on WIMP cross-section below 10^-45 cm^2.

The detector's calibration improved understanding of nuclear recoil signals.

LUX data conflicts with low-mass WIMP interpretations of other experiments.

Abstract

LUX, the world's largest dual-phase xenon time-projection chamber, with a fiducial target mass of 118 kg and 10,091 kg-days of exposure thus far, is currently the most sensitive direct dark matter search experiment. The initial null-result limit on the spin-independent WIMP-nucleon scattering cross-section was released in October 2013, with a primary scintillation threshold of 2 phe, roughly 3 keVnr for LUX. The detector has been deployed at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, and is the first experiment to achieve a limit on the WIMP cross-section lower than $10^{-45}$ cm$^{2}$. Here we present a more in-depth discussion of the novel energy scale employed to better understand the nuclear recoil light and charge yields, and of the calibration sources, including the new internal tritium source. We found the LUX data to be in conflict with low-mass WIMP signal interpretations of other results.