First Results of the LUX Dark Matter Experiment

M C Carmona-Benitez ,L De Viveiros,A Bradley,C Hall,C Chiller,M Woods,A Currie,C Silva,R Webb,D.C Malling,S Fiorucci,C Ghag,C Flores,M Pangilinan,E Druszkiewicz,J.R Verbus,C Nehrkorn,C Zhang,F Neves,M Hanhardt,C.H Faham,A Lindote,M Horn,J Balajthy,C Chan,P Phelps,B Tennyson,D Byram,N Walsh,M Ihm,M Tripathi,A Dobi,T Shutt,C Lee,L Tvrznikova,K Pech,B Edwards,L Reichhart,M Szydagis,M Moongweluwan,S Uvarov,R Knoche,K Kazkaz,P Beltrame,A Manalaysay,M Gilchriese ,I Lopes ,J Möck ,P Sørensen ,E P Bernard ,J E Y Dobson ,N A Larsen ,Di Huang ,E K Pease ,A A Chiller ,D R Tiedt ,James T White ,Jeremy Chapman ,R J Gaitskell ,H N Nelson ,D S Akerib ,V Solovov ,J A Morad ,A St J Murphy ,M S Witherell ,K T Lesko ,K O’sullivan ,S A Hertel ,V M Gehman ,Adam Bernstein ,B G Lenardo ,R L Mannino ,D N Mckinsey ,Adam Bailey ,Xuemin Bai ,D M Mei ,R G Jacobsen ,S J Haselschwardt ,K Gibson ,T J Sumner ,P D Parker ,H M Araújo ,S B Cahn ,R A Ott ,F L H Wolfs ,D J Taylor

doi:10.1016/j.nuclphysbps.2015.09.043

Abstract

LUX (Large Underground Xenon) is a dark matter direct detection experiment deployed at the 4850' level of the Sanford Underground Research Facility (SURF) in Lead, SD, operating a 370 kg dual-phase xenon TPC. Results of the first WIMP search run were presented in late 2013, for the analysis of 85.3 live-days with a fiducial volume of 118 kg, taken during the period of April to August 2013. The experiment exhibited a sensitivity to spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6×10−46cm2 at a WIMP mass of 33 GeV/c2, becoming the world's leading WIMP search result, in conflict with several previous claimed hints of discovery.

Highlights

The observational evidence for the existence of dark matter is overwhelming, mainly due to its gravitational effects
A total of 85.3 live-days of Weakly Interacting Massive Particles (WIMPs) search data were acquired starting in April 2013
The tritiated methane was removed by the purification system using a hot getter. This allowed a high-statistics, homogenous distribution to be acquired for low-energy depositions from β− events within the liquid xenon (EHm3ax = 18.6 keV)

Summary

Introduction

The observational evidence for the existence of dark matter is overwhelming, mainly due to its gravitational effects. A wide variety of cosmological observations support the existence of non-baryonic cold dark matter: galactic rotation curves, the precise measurements of the cosmic microwave background, the study of supernovae and the mapping of large scale structures [1]. Despite this progress, the identity of dark matter remains a mystery. There are different methods that can be used to detect nuclear recoils, including collecting ionization, scintillation, or thermal energy deposition data In this framework, dual-phase liquid xenon detectors are a powerful technology for the direct detection of dark matter [2, 3, 4]

The LUX detector

First LUX Dark Matter search results

Conclusions and outlook