The Present and Future of Searching for Dark Matter with LUX and LZ

Abstract

The LUX collaboration new results advance the search for dark matter candidate particles in the 4 GeV /c 2 and higher mass range, with a maximal spin-independent 90% CL limit of 2 × 10 −46 cm 2 at 50 GeV /c 2 for its 332 live-day run, following after 6 × 10 −46 cm 2 cross-section for 33 GeV /c 2 mass from the re-analysis of its initial 95 live-day WIMP search data from December 2015. LUX has performed multiple advanced in situ neutron and beta/gamma calibrations of light and charge yields down to 1.1 and 0.7 keV, respectively, in nuclear recoil energy and 1.3 and 0.2 keV in units of electron recoil energy, thereby bypassing the past practice of extrapolating yields from ex situ calibrations or simulation models alone. For this conference proceeding, consequences of the new calibrations for the limit on the interaction cross-sections for low-mass WIMPs will be highlighted. Previous claims of a WIMP signal, from other detectors, are now even more strongly disfavored, assuming isospin invariance and the standard WIMP halo model. Both spin-independent and spin-dependent limits will be discussed, including the recent completion of LUX's 332-liveday blind run. Lastly, we highlight the conceptual design and future plan for its 10-ton-scale, next-generation successor LZ, which plans on achieving < 3 × 10 −48 cm 2 sensitivity for a WIMP of mass 40 GeV /c 2 .

New constraints and discovery potential of sub-GeV dark matter with xenon detectors

“…[62] and the S2 efficiency from Ref. [65]; we allow events that satisfy S1 raw > 1 phd, S2 raw > 200 phd. We set an exclusion limit with events measured more than 1 cm from the radial fiducial volume boundary.…”

“…Additionally, for the WS2013 search we include a component for the decays of 127 Xe, which contributed in WS2013 but not in WS2014-16. This simple model provides a good fit to LUX data [67,68] (a comparison is provided in Appendix C). The 90% C.L.…”

Minimal model of gravitino dark matter

“…[13]. In any case, the recent prospects exposed by the LUX [14] and FERMI [15] collaborations showed that the WIMP paradigm should be excluded (or discovered) for dark matter masses below 10 TeV in the present generation of detectors.…”

Right-handed neutrino dark matter in the classically conformal U(1)′ extended standard model

“…6(a), which satisfies all three constraints, the electroweak vacuum stability condition, the LHC Run-2 bound, and the cosmological constraint from the observed RHN DM relic density. The (red) upper solid (dashed) line shows the XENON1T [108] (LUX 2016 [109]) upper bound on σ SI , and the (red) dotted line shows the prospective reach for the upper bound on σ SI in the LZ DM experiment [110]. Figs.…”