We present the first experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at ...the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of \(1.4~\times~10^{4}~\text{kg}\cdot~\text{days}\) of fiducial exposure allows 90% CL upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of \(\sigma_n~=~9.4~\times~10^{-41}~\text{cm}^2\) (\(\sigma_p~=~2.9~\times~10^{-39}~\text{cm}^2\)) at 33 GeV/c\(^2\). The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.
We present measurements of the electron-recoil (ER) response of the LUX dark matter detector based upon 170,000 highly pure and spatially-uniform tritium decays. We reconstruct the tritium energy ...spectrum using the combined energy model and find good agreement with expectations. We report the average charge and light yields of ER events in liquid xenon at 180 V/cm and 105 V/cm and compare the results to the NEST model. We also measure the mean charge recombination fraction and its fluctuations, and we investigate the location and width of the LUX ER band. These results provide input to a re-analysis of the LUX Run3 WIMP search.
LUX is a two-phase (liquid/gas) xenon time projection chamber designed to detect nuclear recoils resulting from interactions with dark matter particles. Signals from the detector are processed with ...an FPGA-based digital trigger system that analyzes the incoming data in real-time, with just a few microsecond latency. The system enables first pass selection of events of interest based on their pulse shape characteristics and 3D localization of the interactions. It has been shown to be >99% efficient in triggering on S2 signals induced by only few extracted liquid electrons. It is continuously and reliably operating since its full underground deployment in early 2013. This document is an overview of the systems capabilities, its inner workings, and its performance.
The design and performance of the LUX-ZEPLIN (LZ) detector is described as of March 2015 in this Conceptual Design Report. LZ is a second-generation dark-matter detector with the potential for ...unprecedented sensitivity to weakly interacting massive particles (WIMPs) of masses from a few GeV/c2 to hundreds of TeV/c2. With total liquid xenon mass of about 10 tonnes, LZ will be the most sensitive experiment for WIMPs in this mass region by the end of the decade. This report describes in detail the design of the LZ technical systems. Expected backgrounds are quantified and the performance of the experiment is presented. The LZ detector will be located at the Sanford Underground Research Facility in South Dakota. The organization of the LZ Project and a summary of the expected cost and current schedule are given.
PreCam, a precursor observational campaign supporting the Dark Energy Survey (DES), is designed to produce a photometric and astrometric catalog of nearly a hundred thousand standard stars within the ...DES footprint, while the PreCam instrument also serves as a prototype testbed for the Dark Energy Camera (DECam)'s hardware and software. This catalog represents a potential 100-fold increase in Southern Hemisphere photometric standard stars, and therefore will be an important component in the calibration of the Dark Energy Survey. We provide details on the PreCam instrument's design, construction and testing, as well as results from a subset of the 51 nights of PreCam survey observations on the University of Michigan Department of Astronomy's Curtis-Schmidt telescope at Cerro Tololo Inter-American Observatory. We briefly describe the preliminary data processing pipeline that has been developed for PreCam data and the preliminary results of the instrument performance, as well as astrometry and photometry of a sample of stars previously included in other southern sky surveys.
