Calibration, event reconstruction, data analysis and limits calculation for the LUX dark matter experiment

TL;DR

This paper details the calibration, event reconstruction, modeling, and statistical analysis methods used in the LUX dark matter experiment, leading to stringent limits on dark matter particle interactions with xenon nuclei.

Contribution

It introduces new calibration techniques, empirical models, and analysis methods that improve the accuracy and reliability of dark matter search results in the LUX experiment.

Findings

Characterized detector performance including efficiencies and stability.

Developed models for drift field, optical properties, and background populations.

Achieved stringent upper limits on dark matter-nucleon scattering cross sections.

Abstract

The LUX experiment has performed searches for dark matter particles scattering elastically on xenon nuclei, leading to stringent upper limits on the nuclear scattering cross sections for dark matter. Here, for results derived from ${1.4}\times 10^{4}\;\mathrm{kg\,days}$ of target exposure in 2013, details of the calibration, event-reconstruction, modeling, and statistical tests that underlie the results are presented. Detector performance is characterized, including measured efficiencies, stability of response, position resolution, and discrimination between electron- and nuclear-recoil populations. Models are developed for the drift field, optical properties, background populations, the electron- and nuclear-recoil responses, and the absolute rate of low-energy background events. Innovations in the analysis include in situ measurement of the photomultipliers' response to xenon scintillation photons, verification of fiducial mass with a low-energy internal calibration source, and new empirical models for low-energy signal yield based on large-sample, in situ calibrations.